If you have root-level access to a server, this means that you will have full control over it. In other words, you'll be able set up any server-side app no matter what the changes that it will make to the software environment on your server, and you will be able to both access and change any kind of file, which includes system files, and modify various settings. This can be done by connecting to the server as a root user that has full privileges to perform all these things as well as to create other users, which includes users who also have full privileges. This particular can be established with a web-based graphical interface or a Secure Shell console. For security reasons, it is recommended that you make a separate user for your daily work and employ the root user only when you have to modify the server or to set up software that may be needed by some script-driven application that you'd like to run.