Email on Status update

Hello,
I want to send a custom email when a request is approved or is refused both have to be sent on an email available in that form.
any custom script and controller that i can refer to do it?

regards,
Oasis

Checkout
https://erpnext.org/docs/user/manual/en/setting-up/email/email-alerts

Thanks revant the issue is how to select the doc.email on the recepient