App Store & iTunes Gift Cards are solely for the purchase of goods and services on the iTunes Store, Apple Books, Apple Music, and the App Store.
App Store & iTunes Gift Cards and Apple Music Gift Cards are specific to your country or region. If you’re trying to redeem an App Store & iTunes Gift Card or Apple Music Gift Card that was purchased in a different country or region, make sure that you’re redeeming it in the iTunes Store for the same country or region.
More info here:
Gift Card FAQs
