in app purchases
How do I stop my daughter from being able to use the credit card I have on file with my Apple ID. She has her own apple id but when she makes in app purchases it charges my card.
Are you using Family Share ? If you are the payment method on the organiser's account will be used (unless she has her own balance on her account). If you are using Family Share you can enable 'ask to buy' on her account : Request and make purchases with Ask to Buy - Apple Support
Or you can use Settings > Screen Time > Content & Privacy Restrictions on her device(s) to block all in-app purchases