Open the Wallet app on your iPhone
Tap the plus sign in the top-right corner
Tap Gift Card
Tap Add Apple Account Card
Tap Continue
Use your camera to scan the gift card code or enter it manually
Follow the on-screen prompts to add the card
If needed, redeem the gift card in the App Store or Apple Account settings first
Check Wallet to confirm the card appears
Use the card from Wallet when making Apple purchases