Open the App Store or iTunes app, tap Redeem, then enter your gift card code to add balance to your Apple ID.
App Store
Open the App Store → go to Account → select Redeem Gift Card or Code, then choose Use Camera to scan the code or enter the code manually. It’s quick and easy, and lets you add balance to use on Apple Music, apps, games, and more.
This activation process is based on Apple’s official documentation. Click