There is no Add button for family sharing option.
On the screen in setting, after you click on your name, and family sharing—- there is not add family member button. Please advise how to add if the button is not present.
Question marked as
Only the organizer can add (invite) new group members. Are you the organizer of the group that set up the group initially? Set up Family Sharing - Apple Support
If it won’t let the organizer add new users, then please contact the Apple Support staff for a deeper dive into the cause for this anomaly.