Navigate to the Control Panel > Money Tab > Admin Functions > Transaction Search.
Use the search panel to find the transaction, then click the Payments icon in the Maintain Column.
On the Payment screen, you'll see all pending payments for the member or non-member. Available credits will also be shown, adjusting the total amount selected for payment.
Select the items the user is paying for with cash or a check. The total will update to reflect the items selected. If the user has a discount code, and the transactions selected are covered under the code, you'll see a box to enter the code.
Use the Payment Method dropdown menu to select either Cash or Check.
Enter in any notes and click Submit Payment.