Gift cards are region-specific. A card purchased in Canada can only be redeemed on an Apple ID set to the Canadian region.
If the camera doesn't work, tap "Enter Code Manually" and type in the code starting with "X". Important Tips for Canadian Users
Once redeemed to your Apple Account, the balance can be used for:
You can often use your device's camera to scan the 16-digit code on the back of the card.
Test Evisort on your own contracts to see how you can save time, reduce risk, and accelerate business.