Secure Shell, also known as SSH, is a cryptographic network protocol employed to execute commands on a remote web server or to exchange data between a web server and a client. Since the info exchanged by the 2 sides is encoded, a 3rd party simply cannot intercept it, which makes SSH a preferred means of managing a website hosting account. The commands that could be executed are determined by the type of hosting service. On a shared web server, for example, the options are limited because you simply won't have root access to the machine, so you can just create/move/delete files, set up and unpack archives, import and export databases, and so on. They're all actions which are carried out inside the shared hosting account and do not need a higher level of access. Using a virtual or a dedicated server, you shall have the ability to set up server-side software or to restart the web server or only a specific service (web server, database server, etc.). SSH commands are submitted via a command line, and if you do not use a UNIX-like Operating System, there are a lot of apps for other OSs, which you can employ to connect to the remote hosting server as well.