1. Go into the ON Persona the Form lives in
2. Go to > Settings > School Forms
3. Click on the Settings for the School Form
4. Select the Reminder Notification tab
5. From the Reminder Option drop down, select Send when activated
6. Set up the rest of the notification settings
7. Click Save & Close

Once this is set up, when the School Form is activated, all Recipients will receive the Reminder Notification