As a rule, receipts are emailed to you by Apple soon after the transaction is completed. However, purchases may be bundled together if you have made multiple purchases, and getting the receipt may take a bit longer. You can check your purchase history by following these steps (iOS 11 and up):
- Go to Settings > [your name] > iTunes & App Store.
- Tap your Apple ID, then tap View Apple ID. You may be asked to verify your Apple ID.
- Scroll down to your purchase history.
- Tap an item to see the date purchase.
- Tap the > icon to the right of the invoice total to see a detailed invoice, including the billing date and order ID.
Follow this article to find your full billing history: https://support.apple.com/en-us/HT204088
All purchases are processed by Apple through iTunes on IOS. If you have any issues with billing or questions about the billing process, you can contact Apple here: https://support.apple.com/contact