How is the secret question password recovery implemented?

Question

PHP

Hello dear.
Faced with the task of implementing a password recovery on a secret question. And before you start designing, I would like to know. As it is implemented in most systems.
1. How and where questions are stored.
2. How the password recovery type is assigned to the user (secret question, sms or mailbox), in a separate table or a field is created in the table with users.
3. Where to store the answers given by the user?