How do I see my purchase history?

Go to Settings on your device, then tap your name, then select iTunes and App Store.
Tap your Apple ID, then tap View Apple ID. You may need to authenticate.
Swipe up to Purchase History and tap it.
Your purchases will be listed, grouped by the date they were charged to your payment method. Items in the Pending section haven't yet charged to your account.
Tap > on any one of the entries to see more details, including the billing date and order ID. You can also get a new email receipt by tapping Resend.

You can also use reportaproblem.apple.com to view your purchases and receipts for past purchases.