Debit cards are connected to a user’s checking/savings account.

Debit cards are processed in two different ways:

“PIN-based” debit requires the customer to approve the payment by submitting their Personal Identification Number (PIN) at the point of sale. Since the customer enters their PIN code, the risk of fraud is reduced which results in lower fees.
“Signature-based” does not require entering a PIN since it is processed like a credit card.