email a password reset link instead of plain password

when a customer forgets password, email a password reset link instead of plain password, the password reset link will also expire after the password reset. If the customer did not reset the password with this link, this link will expire in 24 hours or less. how do we do this? all in a secure manner

Look in the Opencart Extensions, that's the easiest way.
If you cannot find one, then you will have to find a developer to make one for you.

omwtc wrote: how do we do this?

You need to investigate the opencart scripts and start from here

/catalog/controller/account/forgotten.php