Having full root-level access means that you'll be able to access and modify any file on a selected server, in addition to all of the system files, and to change system settings or install server-side software which may be necessary for specific scripts and even offline apps in order to function effectively. A server is accessed at the root level with a root user, who has full privileges to perform all the aforementioned tasks. The root user may also create various other users. For safety reasons, you're advised to have a different account for routine tasks and to use the root account only if you actually need to do some task on your server. The root-level access attribute offers you full control over your server from almost any location, as long as you have the user credentials.
