If you would like to direct a domain address that you have to some other domain address or subdomain, the best way to do that would be to use a CNAME record. By setting up such a record, the domain being redirected loses all its records (A, MX, and so forth) and instead, it takes the A record of the domain name it is redirected to. This way, if you are using a web design service by some company that gives you a subdomain, you can use an actual domain name and not only will it be forwarded to the site which you have set up, but it'll also be displayed in the browser address bar at all times. Alternative possible uses of a CNAME record are to direct all the visitors from various subdomains to their main domain address, or to use the webmail service of your hosting provider by using webmail.your-doman.com, for instance. The latter will work only by setting up a CNAME record for a subdomain since such a record created for the main domain renders it impossible to use email addresses.