What to write in A and mx records for a domain (mail and website) on two IP addresses?

Question

Domain Name System

Good afternoon. I ask for advice.
There is a domain. and there are 2 ip addresses. 1 will be used for the mail server. And the second for the site.
And I want the domain for the mail server to be not mail.xxx.ru, but just xxx.ru ... on which the site will already be.
How to set up A and mx records?
Or you can make a redirect, i.e. the domain was mail.xxx.ru, but there was a redirect somewhere in the records. And all users worked as with @xxx.ru

Answer 1

The mail server domain is mail.xxx.ru
How to send? via a CNAME record?