So, imagine you want to build a house. But first, you need a piece of land to build it on. That land is like a domain name. It's the address where people can find your website on the internet.
But you can't just claim any old piece of land. You have to go to the government (called a "registry") and apply for permission to use a specific piece of land. When you get permission, the government adds your name and the location of your land to a big list they keep, which is like a phone book for land owners.
The same thing happens when you want to make a website. You have to go to a domain registry, which is like the government for website addresses, and apply for permission to use a specific domain name. When you get permission, the registry adds your name and the domain name to the big list they keep, which is like a phone book for website owners.
That way, when someone wants to find your website, they can look in the registry's list to see where to find it. And just like how the government keeps track of who owns what land, the domain registry keeps track of who owns what domain name.