How do I redeem an App store code?

To redeem an App store code on your  iPhone, iPad, or iPod touch manually,

1.  Open the App Store app.
2. Tap Sign-in or your photo at the top of the screen.
3. Tap Redeem Gift Card or Code. If you don’t see this option, sign in with your Apple ID.
4. Tap You can also enter your code manually and follow the instructions. 
5. Enter the 16-digit code that begins with X.
6. Tap Done.

Alternatively, you can also tap the code sent to your email or go to appstore.com/redeem. 

To redeem a gift card on your Android device,

1. Open the Apple Music app.
2. Tap the three dots and then tap Account.
3. Tap Redeem Gift Card or Code.
4. Enter the 16-digit code that begins with X.
5. Tap Redeem.