Use an Apple Gift Card in the Apple TV app on Mac
If you received an Apple Gift Card, iTunes Store Gift Card, or promotional code, you can use it to buy movies and other items in the Apple TV app.
If you haven’t already done so, set up an Apple ID (required before you can redeem anything).
In the Apple TV app on your Mac, choose Account > Redeem, then follow the onscreen instructions.
You don’t need to enter credit card information to redeem only the amount of a gift card.
Your balance appears in the upper-right corner of the screen.
Gift cards are valid only in the country or region where they were purchased.