Online website is a process, here are some basic steps for it
1) You need a domain name that is unique and defines your website that you can buy online such as godaddy.com
Price depends on your name and domain extensions like .com, .in, .net
2) You need hosting which are also available online
3) If you have knowledge of some coding language like html php java then you can use your website and host online website using your description or you can create website
Some are online website builders. This makes setting up a website easy and quick with self hosting and domains for WordPress and Wix
Hope this will help you