A shared mailbox doesn’t require a password and you need to have access to it granted by ITS.
Once you have the access granted, to open the email you need to do the following:
2- On the top right hand side there is a small icon showing your profile picture, please click on it
3- Select: “open another mailbox”
4- insert the shared mailbox address, then OK.
The mail will open in a new tab.
To add this email to your outlook online left pane (folder’s list):
Use the same steps 1 and 2 as above
3- If you don’t see a folder having your name on the left pane, then under folders, click “more” to expand the folder list.
4- right click on your name, then choose “add shared folder …”
5- Type the shared mailbox address and click “Add”
The email will open as a sub-folder withing your email address.
Please let us know if this solves your problem.