Thanks for the message.
The email notification to tell the affiliate that their coupon code was used in an order, and they have earned commission is available in the free version.
You can enable this and customise it in the plugin settings “Emails” tab: https://i.gyazo.com/8ca0ef6b663623b8f0fbe4ecb212c710.png
If the email notifications are not working, see here: https://couponaffiliates.com/docs/my-email-notifications-are-not-working-how-do-i-fix-this/
If you need any more help, feel free to get in touch.