Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
So whats preventing you adding your mail account?
Haver you read the discussion ?
There is a complaint about features lacking in Office 365 Home/Personal. It doesn't help much when you write description how it's done in O365 Business, when people are complaining about those features are missing in O365 home/personal.
Microsoft tell you to upgrade to O365 to use your domain with their services, but they fail to tell you that you need O365 business.