You can register domains in the menu Domain of the customer interface. In the course of the domain registration, you are automatically registered as Admin-C. The same goes for name server registrations, which refer to your server.
In you customer interface you can conduct respective change provider applications. A fax form is generated automatically in this interface, which you can download, fill in and fax or send by mail. That way, you are spared some work, because you don't have to prepare a fax yourself.