Hosting is best thought of as leasing. A provider leases out the resources of its server. You can use those to power a website. Meanwhile, the provider takes care of all the pesky server maintenance so you don’t have to.
You might think an entire server would be too much for a single website—and, in many cases, you’d be right. This is where shared hosting comes in. A provider can let tens or even hundreds of users share a single server.
Users can draw from the same pool of server resources or each user can be allocated a certain amount. This is up to the provider, though the best shared hosting providers tend to prefer the latter.
Either way, it’s an effective arrangement. Shared hosting has made website ownership available to anyone, not just those who can afford their own server.