Open A Shared Mailbox
- Ensure Outlook is the active application
- Click File > Account Settings > Account Settings
- On the Email tab in the list, select the Exchange account, click Change, and then click More Settings
- On the Advanced tab, under Open these additional mailboxes, click Add, and then type the name of the Shared Mailbox you wish to add
Opening A Colleague’s Mailbox
The exact same steps as above will allow you to add another user’s mailbox if you have been granted permission to do so.