Thanks for using/considering our extension (Unfortunately I can only roughly guess what your question is, so feel free to get in touch via our support email)
By default Magento can send the following transactional emails:
1. Order confirmation email
2. Email confirming an invoice
Additionally there are two general approaches to when an invoice in Magento gets created:
1. immediately when the order is placed
2. or as separate step at later stage
Credit card payments usually fall into category 1.) and offline payments like bank transfer or payment by cheque are most likely category 2.)
Which email is send when depends on how the payment method is implemented. Most commonly payment methods that create the invoice directly at checkout (ie credit cards) only send the order confirmation email and never send an invoice confirmation email.
Our extension Email Attachments currently works with the existing emails that your system already sends (ie it doesn't send emails on its own). In conjunction with Print Order Pdf it allows you to:
Attach the order confirmation pdf to the order confirmation
Attach the invoice pdf to the invoice confirmation email
Attach the packing slip pdf to the shipment email
Attach the creditmemo pdf to the refund confirmation email
