If you wish to direct a domain address that you have to another domain address or subdomain, one of the ways to do that would be to use a CNAME record. By creating such a record, the domain being redirected loses all its records (A, MX, and so on) and instead, it takes the A record of the domain name it is pointed to. That way, if you are using a web design service by some provider that gives you a subdomain, you can use an actual domain name and not only will it be pointed to the website which you have set up, but it'll also be displayed in the browser address bar at all times. Other possible uses of a CNAME record are to forward all of the traffic from various subdomains to their main domain address, or to use the webmail service of your webhosting company by using webmail.your-doman.com, for example. The latter will work only by creating a CNAME record for a subdomain because this type of a record created for the main domain address renders it impossible to use email addresses.