Redeeming gift card while living outside US

Where was this gift card purchased?

If it's a US gift card, then it simply needs to be redeemed onto a US account. Physical location during redemption does not really matter.

If you have an Apple account whose region is set to the US, you can redeem a US Apple gift card onto it normally regardless of where you may be in the world physically.

If you currently have an Apple account set to a different country than that of the gift card, then you won't be able to redeem it onto that account.

If you have an Apple Account set to your current country and buy an Apple Gift card in this same country you should be able to redeem it into your account.

Also, this is the Apple (Credit) Card forum, nothing to do with gift cards at all. I'll request the moderators move the to a more adequate forum.

If the gift card was purchased in the US, it can only be redeemed in the country or region (US) of purchase.