Creating a CNAME record for any of the domains or subdomains that you have in a hosting account will permit you to point it to a different domain/subdomain. The forwarded Internet domain will lose all of its records - A, MX and so on, and will take the records of the Internet domain it is being forwarded to. In this light, you cannot create a CNAME record to point your domain name to a third-party company and retain a functional email service with the first hosting company. Also, it is essential to know that a CNAME record is always a string of words and not a number as it's generally wrongly identified as the A record of the Internet domain being redirected. One of the major uses of a CNAME record is to direct a domain name you own through one company to the servers of some other provider in case you have created a site with the latter. In this way, the website will appear under your own domain address, not under some subdomain provided by the third-party company.