Child with greyed out Apple ID can't be part of icloud family storage plan
How to share family icloud storage with 10 year old with greyed out Apple ID?
iPhone 11
There may be restrictions attached to their account. Per this - Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support, try the following...
- Enable Content & Privacy Restrictions, navigate to Account Changes in Content & Privacy Restrictions
- Toggle to "Don't Allow"
- Power Cycle Device
- Navigate back to Settings > Screen Time > Content & Privacy Restrictions > Account Changes
- Toggle to "Allow"
- Toggle off Content & Privacy Restrictions