Vue js how to get postback body?

Question

Vue.js

Hello, there is a problem.
I can’t find a good solution on how to accept a post request on vueJs.
After some actions, I throw it on the form of another site, after which this site also sends the form using the post method to my view back. How to get the body of this postback?
So far, there is only one idea in my head, throw postback to the controller, process the request body there and return the view.