Domain name registatraion just reserves the website name for you like (www.mywebsite.com).

In order for anything to actually appear on that site you have to get web space/hosting and make sure the domain name is "pointing" at the hosting you have.

Domain name reg is like buying a number plate for your car, hosting is like buying a car for your plate.

A web hosting service is a type of Internet hosting service that allows individuals and organizations to provide their own websites accessible via the World Wide Web. Web hosts are companies that provide space on a server they own for use by their clients as well as providing Internet connectivity, typically in a data center. Webhosts can also provide data center space and connectivity to the Internet for servers they do not own to be located in their data center, called colocation.

A domain name registry, also called Network Information Centre (NIC), is part of the Domain Name System (DNS) of the Internet which converts domain names to IP addresses. It is an organisation which manages the registration of Domain names within the top-level domains for which it is responsible, controls the policies of domain name allocation, and technically operates its top-level domain.