The value for the payment type can be set as either of the following:

Variable - This will default to the total of the transaction but allow the operator to change it.

Fixed - The voucher will have a specific monetary value which will be used like cash to reduce the cost of the transaction. If the voucher is worth less than the transaction value then the remainder can be paid by another payment method. If the value is more than the transaction amount it is possible to issue change if payment type is cashable. Also the full value of the fixed amount will be record against the payment regardless of the transaction value.

Transaction Total - This can be set to a percentage of the the total amount. So the voucher could be for a 20% discount on the total price. Setting it to 100% will pay for the full amount and not allow any adjustments.

Product - Using this option will use the price of the product multiplied by the quantity value as the voucher value. This will mean that the value of a voucher could be managed by the product price season. Also the transaction must include the product.