Unixcop published a tutorial about installing Webmin on Ubuntu 21.04.
How to Install Usermin on Ubuntu 21.04
Usermin is a web-based interface mainly for webmail designed for non-root users to perform routine tasks including, reading mail, changing passwords, setting up databases and a web-based SSH terminal. It is a simpler version of Webmin for regular users without always system administrators. It’s a version of Webmin that is for regular users without always system administrators.