Having full root-level access signifies that you'll be able to access and customize each file on a specific server, which includes all system files, and to change system settings or install server-side software which may be necessary for certain scripts and even offline applications 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 things. Your root user may also create various other users. For security reasons, you're advised to have a separate account for everyday tasks and to use the root account only if you actually need to do some task on your hosting server. The root-level access feature will give you full control of your server from any location, as long as you know the user credentials.