If you wish to direct a domain name that you have to some other domain address or subdomain, one of the ways to do this would be to use a CNAME record. By setting up such a record, the domain address being pointed loses all its records (A, MX, and so on) and instead, it takes the A record of the domain name it's forwarded to. That way, if you use a web design service by some provider that gives you a subdomain, you can use an actual domain and not only will it be forwarded to the website 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 forward all of the traffic from different subdomains to their main domain name, or to use the webmail service of your webhosting company by using webmail.your-doman.com, for example. The latter will work only by setting up a CNAME record for a subdomain due to the fact that such a record set up for the main domain name makes it impossible to use email addresses.