1. iTunes Gift Card (US)
Redeem iTunes Gift Card on your iPhone, iPad, or iPod touch
Open Google Play Store app.
Scroll to the bottom of the Featured section and tap Redeem. and Login with your Apple ID.
Tap "You can also enter your code manually."
*If the PIN in link format, kindly open the link in the new browser & copy the code to redeem.
Enter the 16-digit code, which starts with X, retrievable from My Game Card Page.
Tap Redeem. After redeem is successful, your iTunes account balance automatically updates.
Redeem iTunes Gift Card on your Mac
Click Sign In. Then enter your Apple ID and password.
Click your name. Choose Redeem from the menu.
Enter your password again.
Enter the 16-digit code, which starts with X, retrievable from My Game Card Page.
Click Redeem. After redeem is successful, your iTunes account balance automatically updates.