Without somewhere to "store" your website files no one would be able to view your website on their devices connected to the Internet.
Compare it to your home library and the public library.
You have a book. No one can have access to your book or read it without coming to your home right?
Lend the book to the public library and anyone who is looking for that sort of book can check it out and read it.
The library is to a book as hosting is to your website.
ALL websites you have viewed are hosted somewhere.