Setup mail with one mail server?

What is the best approach to offering mail setup etc for me and my clients.
I want all mail to run through
and new users will aim their MX record at
but I am notr sure how I can ensure this works

Currently, for people i add they have their own mail.domain.tld and its good because i know it works but its easier and better if I can point it all to my owns domain server.

Is there any setup steps I need to follow?
Also is there any way I can reflect this in the ‘suggested DNS records’?

I presume you don’t manage the DNS so trying to explain how to set up A records is challenging for non-technical users. Much easier to say ‘see the record that says MX Make it say MX’

So long as you are setting up virtual servers in the normal way, there’s nothing stopping you doing as above. It doesn’t matter what name is looked up to find the mail server, postfix will take care of the message when it arrives.

I don’t know what you mean by ‘suggested DNS records’.

Im thinking he is referring to the dns records virtualmin supplies when a virtual server is created.