Having root-level access to your server signifies that you will be able to view and update any file on it, which includes important system files. You may also install software that can change particular settings on your server during the process, so the installation can be done only if you're logged in as the root user. The latter has full privileges, i.e. you'll have full control over the machine at any time and you can perform anything you want. You can also generate other users either with the same rights or with fewer rights, based on what you need them for - day-to-day tasks, other server administrators, etcetera. 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 you can do through other accounts. You can use a web-based graphical interface or a Secure Shell console in order to connect to the server and to control it at the root level.