Is where you buy a domain name, also known as a url.
While there are companies that offer domain registrar services and also web hosting services, it is important to realise that these are different services and can be purchased from different companies.
A domain registrar is a company that manages the reservation of Internet domain names. They are responsible for maintaining the database of names registered in various top-level domains (TLDs), such as .com, .net, and .org. When a person or organization wants to register a domain name, they must go through a registrar to check the availability of the name and then register it. Registrars also handle the renewal of domain registrations and provide other services such as DNS management.
So in simple terms
A domain registrar is like the librarian of the internet. Just like how a librarian helps you find and check out a book from the library, a domain registrar helps you find and register a website address, like www.example.com. They keep track of all the website addresses that have been taken and make sure no one else can use them. It’s kind of like making sure nobody takes the last copy of Harry Potter from the library.
Also, you need to realise that your domain name can expire and usually needs to be renewed every 12 months, so make sure to keep your email, payment details and contact details up to date at your domain registrar.