A web server is simply a very powerful computer that stores and transmits data across the internet to web site visitors and other web sites. Web servers are one of the most important parts of the internet. Every web site is stored and operated on a web server, so it is impossible to have a web site without also having access to a web server.
There are many different types of web servers available, as well as various server configurations that are designed to provide a wide range of hosting capabilities. Most web servers are connected to the internet throughout the majority of their existence. Web servers are often more expensive than a regular computer, but fortunately web hosting gives site owners the opportunity to lease servers for a nominal cost.