three questions :)

there is a tool to be installed on virtualmin that supervises in a visual way what happens on a domain (emails sent - which email account is sending spam-​​bandwidth used - ETCC ETCC)

There isn't any tracking for how many emails were sent, per-domain.

You can see information about how much bandwidth was used by email though by looking in System Settings -> Bandwidth Monitoring -> Show Usage graph.

in Administrator account can in - Edit User - user - Quota and home directory settings - see the voice - home directory - Instead, when users when they log in as Domain Owner does not have this entry ... how do I enable it?

You can enable the ability for a Virtual Server owner to set a user's home directory by going into System Settings -> Virtualmin Config -> Server Administrator Permissions, and there, you can set "Can select home directories for users" to "Yes".

is there a way to disable sending of mail (smtp) for certain domains?

Virtualmin doesn't currently support a way to disable able sending email. However, we have been exploring the ability to setup email rate limiting on a per-user and per-domain basis, with the help of a Postfix plugin, and we hope to include that functionality in an upcoming Virtualmin version.