How to submit embedded app action using handler:submit

I have create reliable PBX app and make embedded app action for send message from pipedrive to reliable PBX app. and now popup open properly.
But issue for send message action. means i have not any idea for how to get data after form submitted in pipedrive embedded app action. and after send message which action url executed.
open popup called API endpoint url.

So please guide me regarding for this topic and give me solution.

Hi @Kumar_B
Have you checked the following sections in our docs that would be helpful in your scenario?

Do you see the data being posted on your end? Can you share additional details (logs, screenshots, video grab) that would help me understand the scenario much better?