In order to send a password reset to a customer, the first step would be to find that customer's file using one of the searches.
On the right-hand side of the screen under Actions, you will see a Send password reset email link. Click that and you're all set!
Tip: Always keep in mind that a password-reset link within the subsequent email is only valid for one click. In addition, if you resend a password reset it will invalidate all previous password resets sent.