If a user has forgotten their password then they can reset their password by clicking the 'Don't Remember your password?' link on the login screen to the site. As an alternative you can also send the Password Reset as a User administrator.
Go to the Site Login screen and click on the 'Don't remember your password?' option.
Enter the email address address of the user who needs a password reset and click on Submit.
When you click on Submit, an automated email will be sent to the User asking them to follow the steps to enter their new password.
For information on how the User can reset their password, refer them to this article on How do I reset my Forgotten Password.
Note: Once a new Password Reset has been sent to a User it will invalidate any previously sent Password Reset emails to the User.