You have to use the Microsoft 365 admin center or Exchange Online PowerShell to create an Exchange Online user mailbox. You can't create new user mailboxes using the new Exchange admin center (EAC).

Editor's note: Adam Bertram originally wrote this article, and Reda Chouffani has expanded it. Even though administrators can accomplish many tasks with ad hoc PowerShell commands, learning how to ...

Windows PowerShell has long been an IT administrator’s best friend — but only if you know how to use it properly. Created by Microsoft nearly two decades ago, this object-oriented automation engine ...