If I change my Apple ID and then use that to new ID for family sharing, how does my family start sharing using the new ID? Also, can a family member share purchases but also make purchases using their own Apple ID?
iPhone XS Max
If you do a name change, it won't affect Family Sharing.
Note the restrictions in the article.
What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.
To have family members make their own purchases, they can buy/redeem iTunes Gift cards to the account. Charges will be deducted from the account balance before the organizer's credit card is charged.
App Store & iTunes Gift Cards by Email
Changing my Apple ID and family sharing
