Having full root-level access signifies that you'll be able to access and customize any kind of file on a specific server, including all of the system files, and to change system settings or set up server-side software that may be required by certain scripts and even offline apps to work appropriately. A server is accessed at the root level with a root user, who has full privileges to do any of the abovementioned things. The root user can also create other users. For safety reasons, you are advised to have another account for day-to-day tasks and to use the root account only if you actually need to do a specific task on the hosting server. The root-level access function provides you with full control over your server from any existing location, provided that you know the user credentials.