How can I change my adult disabled Child’s Settings to have purchases verified

Read this link please ⬇︎

Approve what kids buy with Ask to Buy - https://support.apple.com/HT201089 - Family Organizer receives requests by default, but another parent or guardian can be assigned permission.

Ask To Buy can only be turned on for members up to 17 (age varies by country - https://www.apple.com/legal/internet-services/itunes/).

Also of possible interest to you ;-) :

Click on the link to read how to 'Update the birth date associated with your Apple ID' - https://support.apple.com/HT204164