Can we send POST data to any page or PHP page only?

Hi,

The thank you page redirects to a custom PHP page in the example.Does it have to be a custome PHP page only ? or can we have some other options ?

Also what if i want to invoke an external api on click of a button on form1 and fill the response of the api in remaining fields on the same form ..how do Igo about doing it.I believe the thank you page will be invoked only when the form is submitted and not when a button on a form is clicked.

The thank you page redirects to a custom PHP page in the example.Does it have to be a custome PHP page only ? or can we have some other options?

You are not required to use PHP. The data can be posted to any page.

Also what if i want to invoke an external api on click of a button on form1 and fill the response of the api in remaining fields on the same form ..how do Igo about doing it.I believe the thank you page will be invoked only when the form is submitted and not when a button on a form is clicked.

We do not allow script injections in the form builder. This should be possible if you use a source code of the form hosted in your custom page with your custom script to accomplish the task.