A web hosting service is the service that allows individuals and organisations to make their website accessible via the World Wide Web. Once your website is created, it needs to be physically somewhere and typing the URL / domain name into a browser, visitors will be able to connect to this space.
It is much like the space that you rent out to have your business in. It’s merely the space itself. It does not include furnishings like shelves for your products, just as the web-hosting account doesn’t include a site for you to sell your products.
Without the hosting services, you won’t have a place for your files to reside, so your domain would then become like a disconnected phone number in the phone directory, and your site files would have nowhere to stay.