Hi
That email is send when the order is created, at the end of the checkout, before sending you to the payment platform.
It's useful for several things:
- people can pay orders not paid immediately.
- website owners can use that for quotations.
- for the notification for order paid via bank transfer, check, credit card collect, western union, etc.
A second email will be sent to the user when the order is confirmed, after the payment.
If you want to deactivate that order creation email, you can disable it via the System>Emails menu in the Business edition.