Ok, I figured out that it is commerce-order-invoice-view.tpl.php in my themes template file. Not sure why or how, but I can modify it and it works great. Now if someone could please oh please tell me how to get this to automatically email when someone completes an order. I see that there is an email button next to the print button in the admin view of the order. On that page the customer's email is there and you just click a button to email them the invoice. Works perfectly. BUT HOW CAN I AUTOMATE THIS AT CHECKOUT?

Thanks.