How To Add Shared Mailbox In Outlook. How to add full access permissions Full access permissions let a user directly sign in to a mailbox by using Outlook or Outlook Web Access OWA and then add that mailbox as a secondary mailbox in Outlook. For Exchange on-premises mailboxes right-click the name of your primary mailbox such as Molly Dempsey in the left navigation pane and then choose Add shared folder.
Click on More Settings. Now it is done and you should see the shared mailbox below your own mailbox folder structure. On the Advanced tab click Add.
However full access permissions do not let the user send as or send on behalf of the mailbox.
To learn more see Compare Groups. It may take a few minutes before you can add members. Those permissions are granted separately. Right-click Folders or your mailbox name in the navigation pane and then select Add shared folder.