These services submit the forms that are required to obtain a domain name for use on your web site. Domain Registration is a service provided by many hosting services, as well as registration services.

There have been many cases where unethical individuals have registered domain names hoping to "sell" the domain to the companies that should have rightfully registered those names. These are not legitimate registration services, and should be avoided. You should not make your web site's name public knowledge until after a domain name has been registered in your name.