For Android Users,

1. Sign in to payment.google.com with your Google Account.

2. Check out your Google Play Store purchase history under pannel "Transactions"

3. Select each transaction that you've purchased.

: Purchase history in Google Play

For iOS Users,

1. Go to reportaproblem.apple.com on your device or PC.

2. Sign in with your Apple account.

3. Click on "See All" under purchase history to check your transaction.

: Purchase history in App Store