auto registering people in the portal after they make a purchase

Hi,
I have Web Portal installed on http://www.aficreditsolutions.com

You can learn about the plugin here:
https://wp-client.com/

I also have woocommerce installed.
https://aficreditsolutions.com/shop/

The site is processing payments using NMI payment gateway. We need it to auto register in the portal after someone buys from the site. How do we do this?