So can i use an existing email address that has my domain name already?

Hi gasservenw,

Yes, you can use an existing email address that has your domain already. This is addressed here:

• "If you have existing email addresses at your domain that you want to keep using, make a list of them so you can configure them in iCloud. If you don’t have existing email addresses, you can create them after you add the domain to iCloud."

You will also find further instructions on getting your Custom Email Domain set up here:

Add an email domain you already own to iCloud Mail on iCloud.com

Take care.