What if I am in us and bought the card in the us?
How to redeem a gift card bought in the us and I live in the us and bought my phone in the us
If your Apple ID is also registered for the US, you should be able to redeem the iTunes gift card.
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Code must be redeemed in a different country or region
If you see a message that says the code must be redeemed in another storefront, the card was probably purchased in another country or region. You can't redeem Apple Gift Cards or App Store & iTunes Gift Cards outside of the country or region of purchase. For example, if you bought an App Store & iTunes Gift Card in France, you can't redeem it in the App Store in the United States.
If you need more help, contact Apple Support.
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copied from: If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support