When you have root-level access to a server, it means that you will have full control of it. In other words, you'll be able install any server-side application whatever the changes that it'll make to the software setting on your server, and you're able to both access and modify any kind of file, including system files, and change various settings. This can be done by connecting to the server as a root user who has full privileges to do all these things and also to create other users, which includes users that also have full privileges. This particular can be established using a web-based graphical interface or a Secure Shell console. For safety reasons, it is recommended that you create a separate user for your daily work and employ the root user only when you have to customize the server or to install software which may be needed by a script-driven application that you want to run.