If you have been given access to another user's mailbox, here are the steps to viewing it:
- Login to Outlook on the web at https://outlook.office.com with your own credentials
- At the top right-hand corner, click on your initials (or profile picture) and choose Open another mailbox.
- Type in the last name of the person whose mailbox you want to view
- The name should appear in the list - click it and click Open
The mailbox will open in another tab.