I hate to be an elitist jerk, but if you can't understand a man page describing a single file format then maybe running an email service is something best outsourced.

I hate to be an elitist jerk, but how am I going to teach my mum to get her email using THAT?!

<3

It is usually not the same people who run it and who create users. You don’t want to bother the admin every time you add a new email address.

But an admin UI is more than just for creating mailboxes. It can also manage quotas, the spam filter, provide setup instructions for the end users, …