You can redeem an Apple App Store & iTunes Gift Card using your iPhone, iPad, Mac, or Windows PC.

Method 1: Redeem via iPhone or iPad (Recommended)

1. Open the App Store on your device.
2. Tap your profile icon (top-right corner).
3. Select "Redeem Gift Card or Code".
4. Use your camera to scan the code or enter it manually.
5. Tap "Redeem", and the balance will be added to your Apple ID.
6. You can now use the balance for apps, games, music, movies, and subscriptions.

Method 2: Redeem via Mac

1. Open the App Store on your Mac.
2. Click on your profile icon or your name at the bottom-left.
3. Click "Redeem Gift Card".
4. Enter the gift card code or use the camera to scan it.
5. Click "Redeem", and your balance will be updated.

Method 3: Redeem via Windows PC (Using iTunes)

1. Open iTunes on your PC (Download from here).
2. Sign in with your Apple ID.
3. Click "Account" → "Redeem".
4. Enter your gift card code and click "Redeem".
5. Your balance will be added to your Apple ID.

Method 4: Redeem via Apple Website

1. Go to Apple’s Redemption Page. 
2. Sign in with your Apple ID.
3. Enter your gift card code and follow the instructions.
4. The balance will be applied to your Apple ID.

Important Notes:

• The balance can be used for App Store, iTunes, Apple Music, iCloud storage, and more.
• Gift cards are region-locked, so they must match your Apple ID country.