Every time i try to enter or take a picture of my gift card it says gift card invalid. I have read above and I’m doing everything correctly so why is it saying this to me

Try this-

1. Make sure that your card is not an Apple Store Gift Card. Apple Store Gift Cards are gray, white, silver, or gold. You can’t redeem Apple Store Gift Cards in the App Store or iTunes Store. Find out what to do if you have an Apple Store Gift Card or don't know what type of gift card you have.
2. Try entering your redemption code manually. When you redeem a gift card, tap or click "You can also enter your code manually." Make sure that you enter the redemption code that begins with "X", not a different number on the card.
3. Make sure that you enter the correct characters. Some letters and numbers look alike, such as B and 8, D and O, E and 3, G and 6, O and Q, O and 0, S and 5, U and V, Z and 2.

If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support