All order invoices will be attached to your order confirmation email. However if the email has been deleted or you can't find it but need a copy of the invoice you will still be able to access them via your Fotofafa account.
1) Log into your Fotofafa account
2) Within the Order History section click on 'Expanded View'
3) Click on 'Completed Orders'
4) Click on the order number whose invoice you would like to view
5) You can also download the invoice as a PDF