You just won money scam
If you get notified by someone claiming to work for Facebook stating you won money either through Facebook, email, or text, it is a scam.
If it comes via email, do not open any attachments. Also don't reply to the email. It lets the scammer know the email is valid.
If it came through message on Facebook, don't reply to it with your personal information. If you did, change your password and contact your credit card and bank (depending on what information you gave them)
There is no reason for Facebook to give money away. They are in a business of making money and not giving it away.