by Manish Kumar.
Hi ,
There are many ways to do authentication for any user. The best way will be email based self registration where every user has to register himself by creating his username and using his email id . Both email id and the username created can be used for further login.
The user has to very the email account and with same verification link The account also gets a confirmation.
You can monitor it
1. Have a list of all users
2. Ask all users to self register with a deadline set
3. Pull a list of users from MOODLE
4. Compare it to your actual list.
5. Ask those who have not registered t Register with in 2nd deadline.