Capture data sent by POST via iframe to another website

:) Hi

I know very little about AngularJS and I'm currently in a blockade that I can't find a solution to.

I have a singlePage in AngularJS which makes a call to some services this OK without problems.

The problem is that another website must use my website, for it iframe will show my page and send me the data I require by POST. My question is how can I capture the data that I send to my website by POST?

I have seen that they can send it to me similar to the answer that they give to a companion of the platform:

Sending data through post method to an iframe

with that solution they send the data by iframe to my website, but I can't find a way or documentation of how I can capture such data.

Thank you very much!