I am setting up family sharing for our phones. My child already has a phone and an account. Every time I try to add a child account, it prompts me to create a new account.. am I able to set her account up as my child without creating a new Apple ID?
iPhone 11 Pro Max
If your child already has an account, then add that account and don't create a new one.
If the child account is under 13 years of age it needs to be tied to a Family Sharing group and as such you would need to have it moved from whatever Family group its currently in to your new Family Group.
Link-> Move a child to another group using Family Sharing - Apple Support
Child account under family sharing
