Assistance and support for Shared Mailboxes and accounts can be found here.
A simple guide on adding an email account to Outlook 2016 and Office 365
How to I send to a local group/contact list in Outlook for Office 365
Confused about your new First.Last name change? Click here for more information!
A guide on how to remove an email account from Outlook 2016
How to move/manage messages automatically with Rules on a Shared Exchange Mailbox
If your Shared Mailbox is unable to send mail, please read this article.