Do Import Files send Receipts?
YES - If importing and charging Credit Card details or Tokens. For this use case, the Payment Txns are created with a Status of "Receipting Complete".
NO - For everything else. The Payments Txns are created with a Status of "Payment Complete". The assumption is the 3rd party system has already generated and sent a receipt.
If you would like to send receipts, then you will need to clone the Payments2Us Workflows that send receipts and adjust these to also send the receipts for import files. If you need a hand with this change, please consult your Salesforce implementation partner or ask us about our Premium Support options to help with the custom setup.