When you have root-level access to a hosting server, it indicates that you will have full control of it. In other words, you can set up any server-side app whatever the changes that it'll make to the software environment on your server, and you can both access and change any kind of file, including system files, and change various settings. This can be done by connecting to the server as a root user that has full privileges to perform the aforementioned things and also to generate other users, including users that also have full privileges. This particular can be established through a web-based graphical interface or a Secure Shell console. For safety reasons, it's recommended that you make one more user for your daily work and employ the root user only when you need to modify the server or to install software which may be required by some script-driven app that you want to run.