The first step to get a website is to register a domain name. Domain registration is how you secure your website address (COM, ORG, NET, etc).
Domains are registered for at least 1 year at a time, and once you have completed domain registration the domain belongs to you until that time ends. You can renew your domain each year or buy multiple years at a time so you don’t have to worry about it. You can even set it to auto-renew to be safe.
A little more in depth:
The Internet Corporation for Assigned Names and Numbers (ICANN) manages the international Domain Name Server (DNS) database. ICANN insures that all registered names are unique and point to a unique Internet Protocol (IP) address. The IP address is the numerical address of the website that tells other computers on the Internet where to find the host server.