Why domain name and hosting is needed?

We all must have seen Godaddy, Hostgator or Hosting ads in our lives on youtube, instagram or google(Chrome) itself.
So what are these hostings and domains?
Domain is something similar to names, just as names are important for us to identify yourself in group of people, it is necessary for your website/app/games to have a name while your hosting, which we call as domain name
So now how do we use domain and hosting actually?
Domain names are on DNS(Domain name server), there are many providers or distributors from whom we can buy domain names.
Examples for this could be godaddy, hostinger, hostgator & namecheap, this list does not end, there are many.
Once we have a domain we need to think of hosting, what is hosting, hosting is server space, or in layman word is a storage somewhere it can be available all the time.

Let's take an example and understand server or domain hosting.

Consider you had a party at your place and everyone is now asking for photos that some or other clicked, but now they are asleep or maybe on work, so those who need photos has to wait, and this is where server(hosting) comes in a picture where everyone will upload photos and anyone needs it can take it from server without being worried if owner of that photo, or the person who first clicked it is available or not.

Now lets understand domain and hosting with a technical hosting method.

You developed or asked Hamiters.com to host your website, if you want your neighbour to use your website you can start your PC or laptop and give remote access, as long your PC or Laptop has power and internet connection you can show your website to them, even for a minute if you looses power or connection your website will go down.
Now it's just a hypothetical method to host a website from the local system, we need something which is always available and works in every condition. Now this is possible with doamin hosting.
Servers are the thing we need, we save(host) our files on the server, and bind it with our domain name while hosting. Using this domain name, you can access files stored on the server.