CNAME
A CNAME is a type of Domain Name System (DNS) used to specify that a domain name is an alias for another domain.
Example: You have a server where you keep all your documents online. It might normally be accessed through docs.example.com. You may also want to access it through documents.example.com. One way to make this possible is to add a CNAME record that points documents.example.com to docs.example.com.
Then when someone visits documents.example.com, they will see the exact same content as found on docs.example.com.
In your domains' list, click the settings icon
Click on DNS editor and add your CNAME