Having full root-level access signifies that you can access and update every file on a particular server, including all the system files, and to change system settings or install server-side software which may be needed by specific scripts and even offline applications to work efficiently. A server is accessed at the root level via a root user, which has full privileges to perform all of the aforementioned things. Your root user may also make various other users. For safety reasons, you are advised to have a separate account for everyday tasks and to use the root account only if you actually need to perform a specific task on the website hosting server. The root-level access attribute gives you full control of your server from any location, provided that you know the user credentials.
