change sending domain in email system

Hello,

I have some so called "normal" issues which I would like to change. Have created a new virtual server with web and email enabled.

But when I am sending the emails from this server they are coming from "this" domain as it`s the name of this virtual server of course , but is it possible to change these settings if yes how and where in the Virtualmin these settings can be changed ... ?

for example, this virtual server is called: mail.test.com and all emails sent from this will use the domain: @mail.test.com and I will change this to: @test.com

Amel