You can pay the ETC fee on the ABC application by the following steps:

1. Open the ABC application and log in to your account.

2. Find "ETC Service" or "Electronic Charge" on the homepage or "My Bank" page.

3. Select "Payment and Recharge" and enter information such as ETC card number and recharge amount.

4. After confirming that the information is correct, select the payment method to complete the payment.