When you have root-level access to a server, this means that you will have full control over it. That is to say, you can install any server-side application whatever the changes that it will make to the software environment on the server, and you're able to both access and update any kind of file, which includes system files, and change any settings. You can do this by connecting to the server as a root user that has full privileges to do the aforementioned things and also to create 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 security reasons, it is recommended that you make a different user for your everyday work and employ the root user only when you need to modify the server or to install software that may be needed by a script-driven app that you would like to run.