Label the card number field to indicate that the user is entering a debit card number or a credit card number.
This is the first time I have paid a vendor using the QuickBooks Invoice Payments Portal. The initial payment screen is set to pay by debit by default. I filled it out with my credit card information believing I was making a credit card payment. When I began paying the second bill, I realized that there was a tab on the top to select credit card payment. Other than the upper tab the two forms are identical. You should indicate by the field where the credit/debit card number is entered if the entry is for a credit card or debit card payment. I have never used my credit card as a debit card. I now need to contact my bank to verify that the card can be used as a debit card and that the payment will be processed.