What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
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.
It is not possible to have two payment options such as product and donation inside of one payment field on the form.
However there is possible workaround. You can set your fields outside of payment field using basic field such as textbox, chackbox, number field, etc. Then you would need to assign values to those fields and to perform calculation inside of the form. Finally you will need to pass calculation to your payment field. This guides can help you to achieve this:
You can also check this thread where my colleague provided detail explanation how this can be done: https://www.jotform.com/answers/601808
Hope this will help. Let us know if you need further assistance.