I always use a gift card to purchase music. I used my gift card a month ago to purchase music. Today, iTunes is asking me to add a credit card even though I have close to $100 gift card balance.
A gift card is a valid payment and shouldn’t be asking me for a credit card.
Payment methods that you can use with your Apple ID - Apple Support
Why is iTunes asking for a credit card now?
Without detailed knowledge of what you own and do, it is hard to give you a simple answer.
Having a subscription, being the Organizer in a Family sharing plan, owing money for a past purchase are among the reasons, including What you can buy with your Apple Gift Card or Apple Account balance - Apple Support
"Some purchases might require that you have a credit card on file, even if you use your Apple Account balance to make the purchase."
Without detailed knowledge of what you own and do, it is hard to give you a simple answer.
Having a subscription, being the Organizer in a Family sharing plan, owing money for a past purchase are among the reasons, including What you can buy with your Apple Gift Card or Apple Account balance - Apple Support
"Some purchases might require that you have a credit card on file, even if you use your Apple Account balance to make the purchase."
iTunes is suddenly asking for credit card
