iOS - How to get an invoice

Invoices are not sent automatically yet.

• PayPal or Stripe users may request an invoice to support@bankin.com
• Purchases made on iTunes store may be viewed in your account purchase history accessible directly.

The full process on iPhone/iPad is described below:

1. Open your Settings > [your name] > iTunes & App Store.
2. Tap your Apple ID, then tap View Apple ID. You might be asked to sign in with your Apple ID.
3. Swipe up to Purchase History and tap it.
4. Tap on the > to the right of the total billed charge to see details of an invoice, including the billing date and order ID.
5. You can tap Resend at the bottom of the invoice details screen to get a new email receipt.

source : Apple’s support page