One of your basic records is proof of payment. You should keep these records to support certain amounts shown on your tax return. Proof of payment alone is not proof that the item claimed on your return is allowable. You also should keep other documents that will help prove that the item is allowable.
Generally, you prove payment with a cash receipt, financial account statement, credit card statement, canceled check, or substitute check. If you make payments in cash, you should get a dated and signed receipt showing the amount and the reason for the payment. "