Odoo Online (Time Off) create custom email once vacation approved/refused

I am new to Odoo Online. I was tasked with setting the time off wherein if vacation request is approved/refused, an email will be sent to the requisting party containing the remaining vacation for the year and a pdf report.

I have tried exploring Odoo Online but was not able to find any email template related to time off vacation request. In addition, how to trigger this email event.

Aside from exploring the email template, I have explored also the developer option for the triggers but was not able to find it.

Thank you in advance.

1. turn on the developer mode
2. settings > technical > email template
3. select the time off model
4. create a template as you like and add the action context (approval email)
5. go to timeoff app and click on the studio icon
6. go to the automation tab > trigger state is set to "approved"
7. from the actions to do tab select the template created before done. better if you do this with a custom module this should be your last resort.