PHP add password and ability to change for user

I’m working on a PHP exercise and need support.

Working off the provided files edit them to provide and ability for the user to determine their userid and to change their password if they forget either. Also provide the ability for the user to change the password whenever they chose. If they are changing their password (when they know the password), they must be required to enter the old password, and then the new password (twice).

Anytime the password is changed it must verify the correct format of the password as previously mentioned in other assignments.