Tap your at the top of the screen. Select "Redeem Gift Card or Code" .
Redeem your gift card in the App Store or the ... - Apple Support how do i buy apps with itunes gift card
Use your device's camera to scan the code, or tap to type it in. Tap "Redeem" to finish. On a Mac: Open the App Store . Click your name or the sign-in button in the sidebar. Click "Redeem Gift Card" in the top-right corner. Follow the prompts to scan the code or enter it manually. Step 2: Buy the App Tap your at the top of the screen