Mar 16, 2023
Click File > Account Settings > Account Settings.
On the Email tab in the list, click the Exchange account type, click Change, and then click More Settings.
On the Advanced tab, under Open these additional mailboxes, click Add, and then enter the mailbox name of the person whose mailbox that you want to add to your user profile. If you do not know the mailbox name, ask the person who granted you Delegate Access permissions.