I am able to send email alert when case is closed.
The email when case closed is marked as 'CASE CLOSED' in email subject:
Basically I want to add email alert when case is closed and send an email to customer that their case has been closed and add the email outbound in case email messages related list.
So, when the customer reply back to a closed email case, the email will be sent back to its related case as inbound email message (customer reply to an 'email-to-case' address)
How to send email alert that act as an outbound email message in case?