When you have root-level access to a hosting server, it indicates that you'll have full control of it. That is to say, you'll be able install 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, which includes system files, and modify any settings. This can be done by connecting to the server as a root user who has full privileges to do all these things as well as to create other users, which includes users who also have full privileges. This particular can be established using a web-based graphical interface or a Secure Shell console. For security reasons, it is recommended that you create a separate user for your daily work and use the root user only when you need to customize the server or to set up software that may be needed by a script-driven application that you want to run.