Green Forms API Send Headers

Can anyone help with how to send API Header with Green Forms via “GET/Post”?

I have sent 3 messages asking for help in the past week. They do not reply.

As the item support is being provided by the author, only help you’d be getting from someone else is gonna be via paid job/help.

If you’re interested in, I don’t mind to check the details. You can contact me anytime.