Can I create promo codes for pages that require a payment?

It will help us provide you with the appropriate response and suggestions if you provide more details on your inquiry.

For now I can only assumed that you could meant using payment field.

There is feature to use promo codes on payment field. That is the Coupon Code feature.

How to Add Coupon Code to Payment Forms

Stripe Forms: Fetch Coupon Code from Stripe

Let us know if you need further assistance.