Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
If you are still using CentOS 7.9, it's time to convert to Alma 8 with the free centos2alma tool by Plesk or Plesk Migrator. Please let us know your experiences or concerns in this thread: CentOS2Alma discussion
You cannot really create a second root user, but you can create a user with root privileges or grant root privileges to an existing user. This needs to be done in Linux, not in Plesk. This article describes how to do it: HowTo: Grant Root Access to User - Root Privileges - Linux - ShellHacks
If you need and additional administrator account in Plesk, go to Tools & Settings > Security > Additional Administrator Accounts
I don't know what permissions a "non-root developer" shall have, so I cannot advise on that.