You cannot disable the penalty for a specific child or invoice in such a way that the parent can pay from the Parent App without the penalty.
However, in the school app, you can manually waive the penalty while marking an invoice as paid.
When you open an overdue invoice in Fee Invoices and click Mark as Paid, Kriyo displays the penalty amount.
Select Waive and Proceed, enter the payment details, and click Save.
For this, the parent must make the payment outside the Kriyo Parent App.