Hi @oleksandr.burla,
Welcome back to the Auth0 Community !
You can send data to your /authorize call using a static parameter as mentioned in our documentation about how to Pass Parameters to Identity Providers. You can make a PATCH request to the Update a connection endpoint and use the upstream parameter.
This community post should come in quite useful as well.
Also, another option instead of using a Post-Registration action is to use the Post-Login action and use methods such as event.stats.logins_count and event.request.query method to achieve your goals.
I hope this helped.
Thanks,
Remus