Apple handles purchases made from within the ForeFlight app. Apple is the only one who can provide a receipt for any purchases made in-app. Apple emails receipts to customers for all purchases, so a receipt for your ForeFlight purchase may be sitting in your email inbox or junk/spam folder.
iPad or iPhone
To retrieve your receipt for your purchase of ForeFlight, from your iPad or iPhone, follow these steps:
STEP 1: Go to the SETTINGS APP.
STEP 2: Tap on your name at the top of the view.
STEP 3: Tap MEDIA & PURCHASES. You might be asked to sign in.
STEP 4: Select VIEW ACCOUNT.
STEP 5: Scroll down and select PURCHASE HISTORY.
STEP 6: Tap on TOTAL BILLED under ForeFlight.
STEP 7: Select RESEND and then OK. The receipt should arrive in your email inbox or junk/spam folder shortly.
From a Mac or PC
To retrieve your receipt for your purchase of ForeFlight, from your Mac or PC, follow these steps:
STEP 1: Open the Music app or iTunes.
STEP 2: From the menu bar at the top of the screen, choose ACCOUNT.
STEP 3: Click VIEW MY ACCOUNT.
STEP 4: On the Account Information page, scroll down to the Purchase History section.
STEP 5: Next to "Most Recent Purchase," click SEE ALL.
STEP 6: Click on the ORDER ID next to ForeFlight.
STEP 7: Select RESEND and then OK. The receipt should arrive in your email inbox or junk/spam folder shortly.
For more information, see this article from Apple:
See your purchase history for the App Store, iTunes Store, and more