Why you would use this feature
If you would like to provide your affiliates with a Shopify coupon code that they can give out to people instead of giving them their affiliate link, this feature is what you would use. When this feature is implemented, if a customers uses an affiliates promo code, they will get a discount for their purchase and the affiliate will get credited their commission for referring the sale.
How to Set it Up
1. Login to your admin control panel and then go to Referral Programs.
2. Now click Promotional Settings and the button that says "Promo Code Tracking"
3. Click "Add Promo Code Tracking" button:
4. Type in the name of the coupon that you created in your Shopify shopping cart, select the corresponding user and then select the referral program:
NOTE: To create a coupon code in Shopify, simply login to your admin control panel and click on "Discounts" on your left navigation and then click the "Add discount code" button.
Once you complete the steps above your affiliates will be able to give out the code you assign for them which will give the customer a discount and calculate a commission for the referring affiliate.