If a Guest selects the pay later option during their purchase the Events Grid will show a Dollar Icon on left side of the row. This Dollar Icon means that there is money owed on that purchase. To add a Payment to that purchase click the Dollar Icon.

Note: this method should only be used if the Event Transaction doesn't have an Invoice attached to it. If there is a connected Invoice you will see a notification in the Payment popup dialog.

This will launch a dialog window where you can select which items you are including in the payment. Once you have selected the items the total will be displayed and you can enter the Payment Type, Check Number if applicable, and include a Memo if desired.  

Before selecting a payment type you have the option to enter in a Coupon Code to give the purchaser a discount on their Pay Later transaction. If payment will be made with a credit card, you can select a card on file, enter a new card and billing information, and choose whether or not to include the processing fees.