*You can deactivate discount codes for a RATE in the "Discounts" tab of the RATE. If a booking has more than one rate the voucher code will be applied to the whole booking.
The voucher code field will appear on the booking page before the first obligatory percentage upsell item or if none, at the end of the upsell items. It will only apply to the items before it not after so you need to arrange the order of the upsell items accordingly.
In REPORTS->CUSTOM REPORTS you can create custom reports which include the voucher codes.