When you have root-level access to a hosting server, it means that you'll have full control over it. In other words, you can set up any server-side app whatever the changes that it will make to the software environment on your server, and you're able to both access and change any file, which includes system files, and change any settings. This can be done by connecting to the server as a root user who has full privileges to perform the aforementioned things and also to create other users, which includes users who also have full privileges. The connection can be established through a web-based graphical interface or a Secure Shell console. For safety reasons, it's recommended that you make a separate user for your everyday work and use the root user only when you need to customize the server or to set up software that may be required by some script-driven application that you wish to run.
Full Root-level Access in VPS Servers
You can take care of your new VPS servers at the root level regardless of the plan that you've chosen, as long as the server is ordered with either the cPanel or the DirectAdmin hosting Control Panel, or devoid of Control Panel at all. In the first case, a number of system settings can be managed via an easy to work with web-based interface, whereas in the second, you will have to do everything through a console, unless you decide to install a Control Panel yourself. Either way, you'll have full control over the VPS as well as any system or custom content on it all the time, which makes this type of web hosting perfect for any application that you can't run with a shared web hosting account because of the restricted degree of access - frameworks, VoIP and audio/video streaming software, etc. The final VPS Control Panel choice is Hepsia, however the root access to your server is restricted.