Hi alycia315,
Welcome to the Apple community where some of us do our best to help each other.
Seems there are a few different apple gift cards.
To find out which ones you have,
and what you can do with them,
Apple has a support page (link below) to help.
https://support.apple.com/en-au/HT204199
and
Scroll down the online Apple Gift Card webpage:
Says:
Redeem Apple Gift Cards or add money directly into your Apple Account Balance anytime.
Then use it to pay for Apple products, accessories, apps, games, music, movies, TV shows,
iCloud, you name it.:
NB: You can click a link to "Redeem", or "add Money"
https://www.apple.com/shop/gift-cards
If needed:
If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card:
https://support.apple.com/en-us/HT201195
All the best :-)