Final answer:
To record a payment made by credit card at the time of purchase, an expense form is used to document the transaction details.
Step-by-step explanation:
A form commonly used to record a payment made at the time of purchase by credit card is an expense form. This form is used to document financial transactions that do not require invoicing or receiving a bill, which typically includes direct purchases or payments.
When the transaction is made, the details of the payment, such as the date, amount, and vendor, along with credit card information, are recorded in the expense form to ensure accurate financial tracking and to maintain record for future reference.