Add Mailbox in Outlook 2010-2016 for Windows With Outlook open, click the File tab. In the Info section, click the Account Settings button then choose Account Settings from the drop-down list. Double-click on your email address in the Name column. The Change Account dialog box opens. Click More Settings button. The Microsoft Exchange dialog box opens. Click the Advanced tab. Click Add button. The Add Mailbox dialog box opens. In the Add mailbox field type the display name (the last name may be enough) of the mailbox you want to add and then click OK. The mailbox name should be added to the Open these additional mailboxes list. Click Apply then OK. On the Change Account dialog box click Next and then click Finish. Close the Account Settings and the Mail Setup – Outlook dialog boxes.