How can this code be directed to any website after sign in e.g. Facebook

Question

https://code.sololearn.com/W5x8GeVUNxtv/?ref=app

Answer 1

Technically you can't math username to their right password of other websites - because you don't have access to their databases. So instead of writing authentication page of your own, you have to work with their APIs (about auth) to do this kind of work.

Answer 2

https://code.sololearn.com/W5x8GeVUNxtv/?ref=app