The first step in gaining a presence on the world wide web is to register a domain name.
The domain name will have to be unique and not registered to anybody else. If your interested in a particular domain name that is already registered you may be able to purchase it from the registered owner but the cost may be extreme.
Securing a domain name is pretty simple, if its available. A search for domain registrars will show many providers.
When you've selected a registrar, enter your desired domain name in the registrars search bar to determine if the name is available for registration. Registration of your domain will have to be maintained either annually or whenever the current registration length has expired. After you've acquired a Domain Name you'll need to point it to the host site where your website files are stored.
In order to provide pages through the world wide web you'll need a web server to store your completed webpage files.
There are serveral providers, which provide the space you need along with 99.9% uptime for accessing and modifying your account. Most providers offer user friendly control panels for uploading pages, creating additional emails and various other options including adding additional domain names, ssl certificates, bulletin boards, image storage, shopping carts etc.The amount of space, number of email accounts and possible allowance of additional domains will depend on the level of service you purchase.
A simple search for domain hosting services will show the top providers.