How to add a shared mailbox
Instructions
How to add a mailbox to your left mailbox view
Go to outlook.office.com and log in.
Right-click on “Folders”
Choose “Add a shared folder”
Type in your store name / or mailbox name
Click “Add”
Now you can find it at the bottom of your list on the left side.
Another possibility is to open a shared mailbox from your online Outlook.
Go to outlook.office.com and log in. Click on your profile icon at the top right and click “Open another mailbox“
Then you can type the mail address in the input box.