How to forward fields with callbacks from a third-party site form?

Question

HTML

For example, a form that is not accessible via api, there is no access to scripts that send responses to the fields https://skys.mozio.com/en-gb/
On our side, we need the same form and calculation of the cost of the trip, address correction.
The parser will handle everything except callbacks. And is there any solution to forward the options offered by a third-party form as the user types?