How to Manage Linux Systems with Webmin : Servers Group
When you first install Webmin on a new VPS, there aren't many options enabled under the Servers menu. As you add more server software and then use the "Refresh Modules" menu option, more will appear on this list.
Read User Mail
To view all of the user mailboxes you want, you must be an administrator. If you use this mailing feature in a group chat, it might be best to refrain from using it.
The last default option is the optional SSH Server. You can use this module to revoke root access through the Authentication menu, among other tweaks. You'll find options that disable password authentication, requiring you to only use cryptographic keys.