Common Name — The fully-qualified domain name (FQDN) — or URL — for which you plan to use your certificate (the area of your site you want customers to connect to using SSL).
An SSL certificate issued for www.coolexample.com is not valid for secure.coolexample.com. If you want your SSL to cover secure.coolexample.com, make sure the common name submitted in the CSR is secure.coolexample.com.
If you are requesting a wildcard certificate, add an asterisk (*) on the left side of the Common Name (e.g., *.coolexample.com or *.secure.coolexample.com).