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 set up any server-side app irrespective of the changes that it will make to the software setting on your server, and you are able to both access and change any file, including system files, and modify various settings. You can do this by connecting to the server as a root user which has full privileges to do all these things and to generate other users, including users who also have full privileges. The connection can be established with a web-based graphical interface or a Secure Shell console. For security reasons, it's recommended that you make a different user for your everyday work and employ the root user only when you have to customize the server or to install software which may be needed by some script-driven application that you want to run.