JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I see that you have used PayPal to collect donations, the coupon option is available for services and products only.
If you want the coupon option to be available you have to switch the type to either products or service.
This guide will provide you with the detailed information required to add coupons to your payment integration
If you need any more assistance feel free to contact us