Google Workspace

https://referworkspace.app.goo.gl/jpQh

Formerly called G Suite.

Formerly Google for Business

and so on.

and so on.

This is a complete domain management system. This is what I have used for Nerd Enterprises, Inc. and I use the Gmail client for my email.

It did take some getting used to at first, but now I could never see going back to MS Outlook.