How to reset the password of the users

I create the user accounts from the web portal. The only thing I create with the new user is username and password. Therefore, I did not set the email address for my accounts.(How to add emails in the web portal?).
The user can not reset their password by sending a email.

Moreover, I can not reset the user's password by the portal. The only way I can reset by the web portal is to delete the user and create a new one. I don't think it is the right way to do this.

You can use occ to reset password of an user:

Users can set e-mail from settings page. See below: