Creating a CNAME record for any of the domain names or subdomains that you've got in a hosting account will allow you to forward it to a different domain/subdomain. The forwarded domain name will lose all of its records - A, MX and so forth, and will take the records of the domain it is being redirected to. In this light, you cannot create a CNAME record to point your domain name to a third-party company and retain a working email service with the first provider. It's also very important to know that a CNAME record is always a string of words rather than a number because it is frequently mistaken for the A record of the domain name being redirected. One of the primary uses of a CNAME record is to direct a domain address which you own through one provider to the servers of another company in case you have created a website with the latter. This way, the site will appear under your own domain address, not under some subdomain provided by the third-party provider.