Q: How can my daughter use her gift cards without it charging my credit card first?

Hi lindafromharvest,

Your daughter and other members of your family group will want to enter any gift cards into their account before making purchases that they want to put on the gift card. To redeem the card see this article -

Redeem iTunes Gift Cards and content codes

Purchases made by accounts with gift balances will be billed before the family sharing credit card. See this article -

How iTunes Store purchases are billed

Thanks for using Apple Support Communities.

Best,

Brett L