I've created a payment plugin for a local system.
After payment confirmed, the status of payment is changed and everything seems OK.
The only matter is after status change no confirmation email is sent to the shopper.
How can I implement that to work?
So, indeed I didn't have to make any program change to sending notifications.
Just needed to go to Configuration->orders-> Default Order Status to send email to shopper->and add statuses where I want the system to send email to the shopper.