When you have root-level access to a server, it means that you'll have full control over it. That is to say, you'll be able set up any server-side application whatever the changes that it will make to the software setting on your server, and you will be able to both access and change any kind of file, including system files, and change any settings. This can be done by connecting to the server as a root user which has full privileges to perform all these things and also to make other users, including users that also have full privileges. The connection can be established with a web-based graphical interface or a Secure Shell console. For security reasons, it is recommended that you create one more user for your everyday work and employ the root user only when you have to modify the server or to install software which may be required by some script-driven application that you want to run.