Sending Email Notification upon every type of Case closure (manually) is possible by a saved search that sends Email Notification when Case changes Stage from Open to Closed or when it changes Status for example from In Progress to Closed.
Steps to create the Saved Search:
1. Navigate to Lists > Search > Saved Searches > New.
2. Select Case as search type.
3. Enter value for Search Title (e.g. Case Closure Notification).
4. Under Results tab > Columns subtab add this field:
5. Click Email tab and then check Send Email Alerts When Records are Created/Updated.
6. Click Recipients from Results subtab, check Send on Update checkbox and as Recipient Field add Email.
7. Click Updated Fields subtab and add:
- For sending the email upon change of Case Stage set:
Field: Stage, When Old Value is: Open, When New Value is: Closed
- For sending the email upon change of Case Status set:
Field: Status, When Old Value is: In Progress, When New Value is: Closed
8. Click Customize Message subtab and enter values for the following fields:
- From – this must be in form "Name" <Email Address>
- Message Field (if this field is populated, no results from Saved Search are sent out, recipients will get only what is entered here)
9. At the bottom of Customize Message subtab uncheck Include View Record Link.
10. Click Save & Run.