I would like to pass only certain form fields as part of the URL as well as some fields that are calculated outside of the form. While I see how to add all form fields, I don’t see anyway to change this option to choose what I want to pass along or augment that with non-form data.
The specific use case would be generating some unique user ID on Page A, stuffing that into a parameter string with some form element, and then picking those up on Page B to do some calculation with.