how do i add apple pay to family share

You’ll need to contact Apple Support to make that change official. It’s a known issue (actually safety and privacy requirement) that Apple needs to participate when the age advances from 12 to 13. It may also take several days for all the Apple servers involved to update to the correct age. If you’re in the US please call 1-800-MY-APPLE or outside the US, consult the support article below for the phone number in your country or region.

Contact Apple for support and service - Apple Support

The first possible limiting restriction is your child’s age. How old is your child?

hi!

as far as i know, only Apple Card is supported by family sharing.

before you start, make sure all people you want to share your Apple Card with are in your family sharing group and at least 13-years old.

to share Apple Card,

1. go into the Wallet app
2. select your Apple Card
3. tap on the three dots
4. tap "Share my Card"
5. invite a family member from your family sharing group
6. add your child as a participant
7. send the invite
8. accept the invite on your child's iPhone