Secure Shell, commonly known as SSH, is a cryptographic network protocol used to execute commands on a remote server or to exchange information between a server and a client. As the data exchanged by the two sides is encrypted, a 3rd party won't be able to intercept it, which makes SSH a favored means of handling a website hosting account. The commands that could be executed depend on the type of hosting service. On a shared hosting server, in particular, the alternatives are limited since you shall not have root access to the website hosting server, so you could only create/move/delete files, create and unpack archives, import and export databases, and so forth. They're all actions which are executed within the shared hosting account and don't require a higher level of access. Through a virtual or a dedicated server, you'll have the option to install server-side software or to restart the hosting server or only a specific service (web server, database server, etc.). SSH commands are submitted via a command line, but if you don't employ a UNIX-like OS, there are a lot of apps for other OSs, that you can employ to connect to the remote server as well.