Add a Second Mailbox to Mac Outlook in 9 Easy Steps

A shared mailbox makes it easy for a group of people to monitor and send email from a public email alias like SMUSharedMailbox@samuelmerritt.edu. When a person in the group replies to a message sent to the shared mailbox, the email appears to be from the shared address, not from the individual user.  A shared mailbox is not designed for direct login, though. The user account for the shared mailbox itself should stay in a disabled state.

Follow these steps to add a shared mailbox you have been granted access to using the Mac Outlook Client.

1. Open the Mac Outlook client.
2. Click the Outlook dropdown on the top bar of your screen and select Settings.
3. Select Accounts.
4. Select the default account and click Delegation and Sharing.
5. Click the Shared with Me tab.
6. Click the +(plus) symbol.
7. In the Search box, type in the email address of the account and click Add.  Use the name of the Shared Outlook Mailbox email address provided to you, i.e. SMUSharedMailbox@samuelmerritt.edu
8. Click OK.
9. Click OK again to finalize.

See:  https://support.microsoft.com/en-us/office/add-an-outlook-com-or-microsoft-365-account-in-outlook-for-mac-37cf645f-0f81-4e88-b5e1-bfe4b20b9b00 for video instructions on how to complete the above steps.