Having root-level access to your server signifies that you'll be able to view and update any file on it, which includes essential system files. You may also set up software that can modify specific settings on the server during the process, so the installation can be performed only if you're logged in as the root user. The latter has full privileges, i.e. you will have full control over the machine at any time and you can perform anything you'd like. You can also create additional users either with identical rights or with fewer rights, based on what you need them for - day-to-day tasks, other server admins, etc. To be on the safe side, it is usually recommended to use the root account only when you actually need it and not for tasks you can do using other accounts. You can use a web-based graphical interface or a Secure Shell console to connect with the server and to manage it at the root level.