All purchases you make are made directly with Apple and developers have no access to your Apple ID information.  Apple does not send email receipts right away under the premise that you may make multiple, low cost purchases in a short amount of time.  This may take a few days to be generated.

You can also find your recent purchases in your App Store purchase history.  Clicking on the preceding link will open the Purchase History screen in the App Store app.  You can find other ways to view your purchase history on Apple products at https://support.apple.com/en-us/HT204088To