Having root-level access to your server signifies that you will be able to view and update any file on it, including important system files. You can also set up software which can update particular settings on the server throughout the, so that the installation can be done only if you are logged in as the root user. The latter has full privileges, which means that you'll have full control over the machine whenever you want and you can perform anything you want. You can also generate other users either with similar rights or with fewer rights, depending on what you require them for - daily tasks, other server admins, etc. To be on the safe side, it's usually recommended to use the root account only when you actually need it and not for tasks that can be done through other accounts. You can use a web-based graphical interface or a Secure Shell console in order to connect with the server and to manage it at the root level.