אכן נחוץ מאוד
You'll have to speak English, this is the only language I understand.
How do i know which country the user registered from, and can i add a country field durring th registration?
You can attempt to locate them based on their IP, which is stored in the db, but there's no guarantee it will be accurate.
You can add a field to registration using a plugin, no way to do it in core.