Microsoft Outlook can be set up to work with existing email accounts to provide a means to search, compose, and reply to email. Outlook's settings and features allow for the user to sync mail between accounts and folders. Adding an additional mailbox to Outlook provides further functionality with existing email accounts.
Open Microsoft Outlook.
Click the "Tools" link in the menu bar and click "Account Settings."
Click "Change" and then click "More Settings."
Click the "Advanced" tab and click the "Add" button.
Type the name of the new mailbox you wish to add and click "OK." Your new mailbox will be listed under "Mailboxes."
Click "OK," then click "Next," click "Finish" and click "Close." Your new Mailbox will be listed along with your previous ones.