Whether its an iTunes Gift Card or a coupon code given by an app developer, there are many different types of Promo Codes. Some give you a specific dollar amount to spend in the iTunes store and others can be for a specific app. You can redeem these promo codes on your PC or Mac in the iTunes Store, but you can also enter them on your iPhone or iPad.
No matter where you redeem your code, it will be available on any device or computer with your iTunes account linked to it. For instance, if you redeem a code on your iPad, you can use that credit on your Mac as well.
To redeem a Promo Code, tap on the iTunes Store icon from the iPad homescreen.
This will open the main iTunes store window. Make sure you’re on any other tab than the Downloads tab.
Scroll down to the very bottom of the iTunes Store page and you will see the Redeem Button. Tap on it to enter your promo code.
A pop-up window will appear with a text field to enter your code. Type in the code and tap on Redeem.
If the promo code is a numerical value, it will be redeemable in both the iTunes and App Stores.