M365 - Open and use a shared mailbox in Outlook on the web

Some users are granted access to shared mailboxes.  The link below will show you a guided video on how to access them on using outlook on the web.  Once you follow those instructions, it will also force the shared mailbox to show up conveniently in your local Outlook account within about 2 hours.

https://support.microsoft.com/en-us/office/open-and-use-a-shared-mailbox-in-outlook-on-the-web-98b5a90d-4e38-415d-a030-f09a4cd28207