In order to charge a parent's payment method, first make sure the parent has added a payment method through their app. From your Admin Dashboard, click on the Student's name from the roster. Click "Payments" at the top and scroll all the way down to the Payment Methods section. Once you've confirmed a payment method is listed, scroll back up to the top of the Payments tab. Click the drop-down menu on the blue "Add payment" button and then click "Charge payment". This will charge the default payment method on file for this student. The amount charged will be in the second yellow summary section that shows the amount and due date. In the example below, $1,000 will be charged.
You'll be taken to the Create a new payment screen. Add the payment method from the drop-down menu or add a new payment method. Enter an amount to charge, description, and select if this should create a new item. Click "Charge" in the bottom right corner.