/whmcs-module/preliminary-operations/set-up-the-domain-register
Set up a domain registrar
3.1
From the selection menu at the top right, click on the setup button 
and select
System Setting > Active your first domain registrar
from the drop-down menu on the right (if you have already set up a Domain Registrar go to 3.3).
3.2
Choose the “Email Notification”module and configure it with the email address where you want to receive WHMCS notifications to.
3.3
If not already set up, add an accepted payment method via “Activate Your First Payment Gateway” " (if you have already set up a payment gateway go to point 4.1).
