Open a Shared or Delegated Mailbox
Use this method if you are a delegate for another user’s mailbox or when you have permissions to several folders in a shared mailbox. You can also use this method when you have full access permissions to a mailbox.
To open the shared mailbox:
In the Tools menu, choose Accounts, and select the account that has access to the mailbox.
Select Delegation and Sharing
Choose Shared With Me tab
Choose + to add a shared or delegated mailbox
Open a Shared Calendar
On the File menu, point to Open, and select Other User's Folder...
In the Folder Type list, choose Inbox, Calendar, or Address Book.
Note: In the new Outlook for Mac, you can only choose calendar.
In the Search box, type the name of the person who granted you access, select the person's name in the search results, and choose Open.
The shared Mail folder appears under folders.
The shared Calendar appears in the Folder pane under the Shared Calendars heading.
The shared Address Book appears in the Folder pane under the Shared Contacts heading.