Having full root-level access means that you'll be able to access and customize any file on a selected server, which includes all of the system files, and to change system settings or install server-side software that may be needed by specific scripts and even offline applications in order to work properly. A server is accessed at the root level through a root user, who has full privileges to perform all the aforementioned tasks. Your root user can also make other users. For security reasons, you are advised to have another account for routine tasks and to use the root account only if you actually need to do some task on the website hosting server. The root-level access function will give you full control over your server from any location, given that you know the user credentials.