Having root-level access to your server means that you will be able to view and modify any file on it, which includes essential system files. You can also install software which can modify certain settings on the server during the process, so that the installation is possible only if you are signed in as the root user. The aforementioned has full privileges, i.e. you will have full control over your machine whenever you want and you can do anything you want. You may also generate additional users either with identical rights or with fewer rights, based on what you require them for - day-to-day tasks, other server admins, etc. To be on the safe side, it is generally recommended to employ the root account only when you actually need it and not for tasks that you can do through other accounts. You may use a web-based graphical interface or a Secure Shell console to connect with the server and to control it at the root level.