How to Add Members to a Shared Mailbox in Microsoft 365

September 13, 2023
13 min read

In the previous article, you saw how you can create a shared mailbox. Now I'll show how you can add members and assign them with the shared mailbox permissions such as Read and manage, Send as, and Send on behalf of, so that they can start using the shared mailbox. You can do this with the following methods:

  • Using the Microsoft 365 admin center
  • Using the Microsoft Exchange admin center (EAC)
  • Using Windows PowerShell

This article discusses all three methods.

For those who like to watch and learn, check out the 20-minute video at the end of this article.

A Brief Note on Shared Mailbox Permissions

You can assign mailbox users the following permissions:

  • Read and manage: This allows shared mailbox users not only to read mails sent to the shared mailbox but also take actions like deleting emails, folders, etc.
  • Send as: This allows shared mailbox users to send emails from the shared mailbox.
  • Send on behalf of: This allows shared mailbox users to send mail on behalf of the shared mailbox. The recipients of the mail will know that a specific user sent the mail on behalf of the shared mailbox. Example: bina verma on behalf of legal [with legal being the shared mailbox belonging to the legal team].

Prerequisites

To add members to a Microsoft 365 shared mailbox, you must have a global administrator or Exchange administrator role assigned to you.

Using the Microsoft 365 Admin Center

To add members to a Microsoft 365 shared mailbox using the Microsoft 365 admin center:

Sign in to your Microsoft 365 tenant using your credentials. From the left pane, select the Admin icon, as shown in Figure 1. Doing so opens up the Microsoft 365 admin center.

This screenshot shows where the admin icon is located in the Microsoft 365 home page.
Figure 1: Admin icon on the left pane of Microsoft 365 home page. | Used with permission from Microsoft.

From the menu, select the Teams & groups > Shared mailboxes option, as shown in Figure 2.

This screenshot shows how you can access the shared mailboxes page from the Microsoft 365 admin center.
Figure 2: Accessing the Shared mailboxes page from the Microsoft 365 admin center. | Used with permission from Microsoft.

Choose the shared mailbox to which you wish to add members by selecting it. Doing so opens the Shared mailboxes details pane to your right, as shown in Figure 3. 

This screenshot shows how you can add members to a shared mailbox by clicking the edit link available under the members section of the mailbox details pane.
Figure 3: Shared mailboxes details pane. | Used with permission from Microsoft.

Under the Members section, select the Edit link. Doing so opens the Shared mailbox members pane, as shown in Figure 4.

This screenshot shows how you can add members to a shared mailbox by clicking the Add members button in the mailbox details pane.
Figure 4: Add members option. | Used with permission from Microsoft.

Select Add members. All your Microsoft 365 users get listed. Select the users you want to add as members to the shared mailbox, and then select Add, as shown in Figure 5.

This screenshot shows how you select members to be added to a shared mailbox using the shared mailbox details pane.
Figure 5: Adding members to the shared mailbox. | Used with permission from Microsoft.

A confirmation message about the shared mailbox members ("Saved") appears, as shown in Figure 6.

This screenshot shows the confirmation message which shows up when you add members to a shared mailbox.
Figure 6: Confirmation message that shared mailbox members have been added. | Used with permission from Microsoft.

Note: Members added to a shared mailbox using the Microsoft 365 admin center get assigned the Read and manage permissions and Send as permissions by default.

Assigning Shared Mailbox Permissions to Users

You can modify the default permissions assigned to users.

To assign shared mailbox permissions (or modify existing permissions):

Select the name of the shared mailbox. Doing so opens the Shared mailboxes details pane to your right. Scroll down to the Manage mailbox permissions section. Select the permission you want to assign by selecting it: for example, Send as permissions, as shown in Figure 7.

This screenshot shows how you can access the shared mailbox permissions available under manage mailbox permissions section of the shared mailbox details pane.
Figure 7: Assigning Send as shared mailbox permissions to users. | Used with permission from Microsoft.

You will see a list of your existing shared mailbox users, as shown in Figure 8. Select Add permissions.

This screenshot shows the add permissions button using which you can add shared mailbox permissions to the members of a shared mailbox.
Figure 8: Select Add permissions. | Used with permission from Microsoft.

All your Microsoft 365 users get listed, as shown in Figure 9. Select the ones you wish to add (and assign permissions to) to the shared mailbox, and then select Add.

This screenshot shows how you can select users to be added to a shared mailbox and assign them with appropriate mailbox permissions.
Figure 9: Selecting users to be assigned with shared mailbox permissions. | Used with permission from Microsoft.

The selected permission—be it Read and manage, Send as, or Send on behalf of—gets assigned, as shown in Figure 10.

This screenshot shows the confirmation message which gets displayed when you add members to a shared mailbox and assign them with appropriate mailbox permissions.
Figure 10: Send as shared mailbox permission successfully assigned to users. | Used with permission from Microsoft.

Note: You can also remove the assigned shared mailbox permission by selecting the user, and then selecting Remove permissions at the top, as shown in Figure 11. Multiple user selection is also possible.

This screenshot shows how you can remove assigned mailbox permissions from a user.
Figure 11: Removing assigned shared mailbox permission. | Used with permission from Microsoft.

Using the Microsoft 365 Exchange Admin Center (EAC)

To add members to a Microsoft 365 shared mailbox using the Microsoft 365 EAC:

From the Microsoft 365 admin center, select Show all, as shown in Figure 12.

This screenshot shows the show all option within the Microsoft 365 admin center.
Figure 12: Show all option in the Microsoft 365 admin center. | Used with permission from Microsoft.

From Admin centers, select Exchange, as shown in Figure 13.

This screenshot shows how you can access the exchange admin center from the menu of the Microsoft 365 admin center.
Figure 13: Accessing the Exchange admin center. | Used with permission from Microsoft.

Select the shared mailbox you want to add members to. Doing so opens the Shared mailboxes details pane to your right, as shown in Figure 14. Select the Delegation tab. Using the Edit buttons, you can add members to the selected shared mailbox and assign them the appropriate permission. For example, you can use the Edit button below Send as to add shared mailbox members with only Send as permission.

This screenshot shows how you can access the shared mailbox user permissions available under the delegation tab of the shared mailbox details pane.
Figure 14: Adding members to a shared mailbox using the Exchange admin center. | Used with permission from Microsoft.

Selecting one of the Edit buttons opens the Manage mailbox delegation pane, with an Add members option, as shown in Figure 15.

This screenshot shows the add members button available within the shared mailbox details pane.
Figure 15: Add members option. | Used with permission from Microsoft.

Select Add members. Doing so lists all your Microsoft 365 users, as shown in Figure 16. Select the ones you wish to add (and assign permission to) to the shared mailbox, and then select Save. 

This screenshot shows how you can select users to be added to a shared mailbox using the Microsoft 365 admin center.
Figure 16: Selecting users to be assigned with the shared mailbox permissions. | Used with permission from Microsoft.

You have to confirm your action, as shown in Figure 17.

This screenshot shows the confirmation message which shows up when you add users to a shared mailbox and assign them with appropriate mailbox permissions.
Figure 17: Confirm addition of shared mailbox member. | Used with permission from Microsoft.

A "Mailbox permissions were added to these mailboxes" success message gets displayed, as shown in Figure 18.

This screenshot displays the success message which shows up when you complete adding members to a shared mailbox.
Figure 18: "Mailbox permissions were added to these mailboxes" success message. | Used with permission from Microsoft.

Note: You can also remove the assigned shared mailbox permission by selecting the user and selecting Delete at the top, as shown in Figure 19. Multiple user selection is also possible.

This screenshot shows how you can delete or remove mailbox permissions from a shared mailbox user.
Figure 19: Removing assigned shared mailbox permission. | Used with permission from Microsoft.

Using PowerShell

To add members to a Microsoft 365 shared mailbox using PowerShell:

Open your PowerShell console as Administrator, as shown in Figure 20.

This screenshot shows how you can run your Windows PowerShell in administrator mode.
Figure 20: Running PowerShell as Administrator. | Used with permission from Microsoft.

To connect with your Microsoft 365 Exchange Online, run Connect-ExchangeOnline and provide your sign-in credentials, as shown in Figure 21. For more information, read How to Connect to Microsoft 365 Exchange Online With PowerShell.

This screenshot shows how you can connect to Microsoft 365 exchange online using Windows PowerShell.
Figure 21: Connecting to Microsoft 365 Exchange Online. | Used with permission from Microsoft.

Once you are signed in, run the following scripts to provide your shared mailbox users with fullaccess, sendAs, and sendOnBehalf shared mailbox permissions respectively.

  • Assigning fullaccess permission: As shown in Figure 22, run the following command:
    Add-MailboxPermission -Identity legal -AccessRights FullAccess -User akash@acerscorp.onmicrosoft.com 
    Note: FullAccess (Read and manage) permission means the user has the right to read and manage the shared mailbox, but won’t be able to send any mail.
This screenshot shows the PowerShell script for adding the full access shared mailbox permission to a Microsoft 365 user.
Figure 22: Granting Read and manage shared mailbox permission using PowerShell. | Used with permission from Microsoft.
  • Assigning SendAs permission: As shown in Figure 23, run the following command: Add-RecipientPermission -Identity legal -AccessRights Sendas -trustee akash@acerscorp.onmicrosoft.com 
    Note: Send as permission means the user only has the right to send emails from the shared mailbox address and won’t have direct access to the mailbox itself.
This screenshot shows the PowerShell script for adding the send as shared mailbox permission to a Microsoft 365 user.
Figure 23: Granting Sendas shared mailbox permission using PowerShell. | Used with permission from Microsoft.
  • Assigning SendOnBehalf permission: As shown in Figure 24, run the following command: 
    Set-Mailbox -identity legal -GrantSendOnBehalfTo akash@acerscorp.onmicrosoft.com 
    Note: Send on behalf of permission means the user only has the right to send emails on behalf of the shared mailbox and won’t have direct access to the mailbox itself.
This screenshot shows the PowerShell script for adding the send on behalf shared mailbox permission to a Microsoft 365 user.
Figure 24: Granting Send on behalf of permission using PowerShell. | Used with permission from Microsoft.
  • Adding multiple users to a shared mailbox (and assigning permission to them): As shown in Figure 25, run the following command: 
    forEach($user in $users){Add-MailboxPermission -Identity legal -AccessRights FullAccess -User $user} command. Ensure that the users to be added are saved in the $users variable.
This screenshot shows the PowerShell script for adding multiple Microsoft 365 users to a shared mailbox and assigning them with full access permission.
Figure 25: Adding multiple users to a shared mailbox using PowerShell. | Used with permission from Microsoft.
  • Removing Shared Mailbox permissions: As shown in Figure 26, to delete the user from the shared mailbox and remove the shared mailbox permissions associated with the user, run the following command: 
    Remove-MailboxPermission -Identity legal -User akash@acerscorp.onmicrosoft.com -AccessRights FullAccess 
This screenshot shows how you can remove the shared mailbox permission from a Microsoft 365 user.
Figure 26: Deleting users from a shared mailbox and removing their permissions. | Used with permission from Microsoft.

Adding a Shared Mailbox to Outlook

Users with a shared mailbox permission can add them to their user mailbox and start using them. To add a shared mailbox:

Access the Outlook app from the Microsoft 365 home page. Right-click on Folders and select Add shared folder or mailbox, as shown in Figure 27.

This screenshot shows how you can access the add shared folder or mailbox option in the Outlook app.
Figure 27: Add shared folder or mailbox option in Outlook. | Used with permission from Microsoft.

Search for the shared mailbox and then select it, as shown in Figure 28.

This screenshot shows how you can search for a shared mailbox in the Outlook app.
Figure 28: Searching for a shared mailbox in Outlook. | Used with permission from Microsoft.

Select Add, as shown in Figure 29.

This screenshot shows how a Microsoft 365 user can add a shared mailbox using the Outlook app.
Figure 29: Adding a shared mailbox. | Used with permission from Microsoft.

The shared mailbox gets added to the user inbox, as shown in Figure 30.

This screenshot shows how a shared folder appears in the Microsoft 365 user inbox.
Figure 30: Successfully added shared mailbox folder. | Used with permission from Microsoft.

Sending Emails from a Shared Mailbox

Microsoft 365 users assigned with Send as and Send on behalf of shared mailbox permissions can send emails using the shared mailbox’s email address from Outlook.

Using Send As Shared Mailbox Permission

To send mail using the shared mailbox email address:

Sign in to the Microsoft 365 portal using your credentials. From the left pane, select Outlook, and then select New Mail.

This screenshot displays the New mail button available in the Outlook app.
Figure 31: New mail button. | Used with permission from Microsoft.

From the Options menu, select the Show From checkbox. Doing so displays the From email address field, as shown in Figure 32.

This screenshot shows how you can display the hidden from email address field by accessing the options menu and enabling Show From checkbox in the Outlook app.
Figure 32: Accessing the From email address field. | Used with permission from Microsoft.

Click the From address field, and then select Other email address, as shown in Figure 33.

This screenshot shows how a Microsoft 365 user can add a shared mailbox address to the from email address field.
Figure 33: Adding shared mailbox email address. | Used with permission from Microsoft.

In the From email address field, enter the shared mailbox email address. If the user has the Send as permission, the shared mailbox email address pops up, as shown in Figure 34. Select the email address and send the mail to it.

This screenshot shows how you a Microsoft 365 user can search for a shared mailbox email address in the Outlook app.
Figure 34: Search for shared mailbox email address. | Used with permission from Microsoft.

Using Send on Behalf of Shared Mailbox Permission

Users with Send on behalf of permission enabled can also add the shared mailbox address to the From email address field (as explained earlier) and send emails using it. The only difference is that the recipients of the mail will know who sent the mail on behalf of the shared mailbox, as shown in Figure 35.

This screenshot displays how a mail sent from a Microsoft 365 user with a send on behalf shared mailbox permission appears in the Outlook app.
Figure 35: Mail recipients will know who sent the mail on behalf of the shared mailbox. | Used with permission from Microsoft.

Conclusion

In this final article on Microsoft 365 shared mailboxes, you learned how to add members to a Microsoft 365 shared mailbox and assign mailbox permissions to them using the following:

  • The Microsoft 365 admin center
  • The Microsoft 365 Exchange admin center
  • PowerShell

In upcoming articles, let’s start exploring Microsoft 365 Exchange admin center and how you can use it for Microsoft 365 mailbox management.

For Those Who Like to Watch and Learn

The following video is a 20-minute version of this article. It shows you add members to a Microsoft 365 shared mailbox and assign permissions using the Microsoft 365 admin center, the Exchange admin center, and PowerShell.

 

Thilak Kumar Singh

Thilak Kumar Singh

Thilak Kumar Singh is a trainer who believes in teaching about IT in the simplest possible way with more emphasis on visual mode of learning. He firmly believes in democratizing IT knowledge, especially of Microsoft solutions, in which he specializes as a trainer and consultant.

He observes that in this era dominated by cloud computing and collaboration, where IT has reached users unimaginable hitherto, IT knowledge must not be an obscure science, but rather be available to anyone who wishes to engage with IT. 

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