Only the admin of the school can add all the parents in the school to the PTA group. 

To add all the school parents to the PTA group - 

  • Click on the school in the left menu
  • Click Manage
  • Click Parents
  • Click on the circle to the left of a parent 
  • Click Select all / select the parents you want to add
  • Click +class/group
  • Click PTA Group/ other groups
  • Click Members

This will add all the parents to the PTA group.