A web host. A web host is a service which puts a website on the Internet allowing web surfers to search, find and view the website easily. often the people or groups who host the websites are the people who design them
How much will it cost?
There is some attached costs for the use a web host's service's. The higher the cost the more control one would have over things such as the layout and the amount of content allowed on the website.
What is a domain name and how would you register one?
A domain name is a recognizable name or word which precedes ".com" ".co.uk". etc domain names are like the post codes of websites, but without the numbers. Just like a postcode, each domain name is unique and individual. and leads to only one address.
To register a domain name you would have to go through a variety of choice companies to register the name for you, obviously the name of your choice would have to be available before you make it your own, and if not you could always offer to buy a domain name from its current owner.