Having root-level access to your server means that you will be able to view and modify any file on it, including essential system files. You may also set up software that can update certain settings on the server during the process, so the installation can be done only if you are logged in as the root user. The aforementioned has full privileges, i.e. you will have full control over the machine at any time and you will be able to perform anything you would like. You may also create various other users either with similar rights or with fewer rights, according to what you require them for - daily tasks, other server admins, etcetera. To be on the safe side, it is usually recommended to employ the root account only when you actually need it and not for tasks which can be done using other accounts. You can use a web-based graphical interface or a Secure Shell console to be able to connect with the server and to manage it at the root level.