On our dedicated and Virtual Private Linux servers, "root" is the administrative user that you can use to access and edit all of the files on your server (this includes system-critical files). You can also use root to install and uninstall programs on your server.
However, using root on your server can be dangerous. When you work on your server as root, you can potentially destroy important files and delete programs on accident. Typically, you should only use root to make one or two changes to your system and then switch back to your normal user account.
For more information, see Switching to the Root User on Your Linux Server.