Please note, the unified experience of Outlook “new” means that these instructions may work in OWA and MacOS versions of Outlook.
Step 1
From the File menu choose Account Info to open the Settings window to the Your accounts page.
Step 2
Choose the Shared with me tab and click the +Add button.

Step 3
In the Add a shared email account type in the email address, displayname, or username/alias of the shared mailbox. In some instances, the interface will complete and show search results in others, it wont.
For instance, in the screenshot to the left, the example@ufl.edu address was not found. The address can still be entered and the Continue button clicked. Your access will be granted if it is a valid mailbox that you have permissions to access.

