How is the Facebook registration form made?

Question

Facebook

Hello!
Can you please tell me how the registration form for the seminar was made in the Facebook feed?
1. screenshot of the feed, click in the projection of the red rectangle

2. screenshot of the resulting form

Are you interested in native Facebook functionality or custom? It is in the case shown.
Who in the subject, help, please. I also need to register for seminars in social networks, but neither Google nor the documentation helped. I only came across some third-party solutions.
Thanks in advance!

Answer 1

This is a built-in form of lead generation. Read more here https://developers.facebook.com/docs/marketing-api...