Having full root-level access signifies that you can access and modify any kind of file on a particular server, including all the system files, and to change system settings or set up server-side software which may be required by certain scripts and even offline applications in order to function properly. A server is accessed at the root level via a root user, who has full privileges to perform all of the aforementioned tasks. The root user can also generate various other users. For safety reasons, you're advised to have another account for routine tasks and to use the root account only if you actually need to do some task on your website hosting server. The root-level access function provides you with full control of your server from almost any location, given that you know the user credentials.