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Sign into your email account and go to Outlook.
In the upper right corner, click the circular icon with either your initials or your profile picture, then click "Open another mailbox".
You will be prompted to enter in another mailbox. Enter the shared email address. After a moment, the inbox from that shared account should be shown alongside of your normal emails.
In the Old Version of Outlook on the
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Desktop App:
Click File > Open and Export > Other User's Folder
You will be prompted to enter something next to a button labeled "Name". Enter the shared email address.
Make sure the folder type is set to "Inbox" and click "OK". After a moment, the inbox from that shared email should be shown alongside of your normal emails.
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