How to auto create DNS for subdomains from WHMCS

dns

#1

Hello,
I need help from the experts here. I’m using the following solutions.

1- WHMCS
2- Plesk server

All my clients using their applications from my server through subdomains. I want to auto create the subdomain DNS in CloudFlare once they placed the order.
CloudFlare addon already added to WHMCS and client can choose it when placing order.
My problem is the service still pending even after accepting the order. My CloudFlare partner account is new and have no domains yet.