New users are approved by a School Ambassador (the person who initially signed up your class) or Class Rep. These will typically be parents who are already involved in the PTA or school community, whose identity has been confirmed by Classlist upon registration.
In turn, Ambassadors and Reps are responsible for approving parents and making sure all applications are genuine. This is normally done very quickly, as it involves fairly basic checks relating to contact details. Classlist’s offers plenty of support and advice to those involved in the approval process to ensure it is done in a safe, efficient manner.