I was wondering how a hosting company can verify that you own a domain from another company that registers domains. I know that you change the DNS at the register site, and that you put the website in hosting company's site, but is that all? Thanks!
That's all there is to it. the hosting company takes your word for it that you own the domain. If you cannot change the DNS to point to their servers, then you don't own it. Either way they are happy to keep your money. The only reason they need to know your domain is that in a shared hosting environment your domain shares an IP with other domains and they need to tell the web server which of several accounts to serve the pages from. If you wanted to have several domains resolve to the same site in a shared hosting environment then they'd need to point all of the possible domains to a single account - for which they'd charge you more.