Everyone that sets up a web site needs a way to get their information onto the internet where other people can access it. Not everyone needs a web host, but if you do not use a web hosting service then you must provide your own server. Providing your own server also comes with the headaches of maintaining the server, and it also requires some in depth computer knowledge to make it all function correctly.
Most people simply choose to hire a cheap web hosting uk company to get their server space from. Then the host is responsible for all the upkeep and maintenance. When you hire a host they essentially rent you some of their available server space for a fee. The larger companies will provide you with more space and with higher bandwidths so that you site loads for your customers at a reasonable speed. The smaller companies will offer you a better quality of customer support and service.
It is really up to you to research all the many hosting services they are and find one that has all the tools you need, for a price you are willing to pay. If you are really new at this you might want to try going with one of the big names like Google or Yahoo, as a web host.