To use Voucher Codes in Sixt shopping, you only need to do the following three steps: 1. Log in or create a new account on sixt.co.uk. Select the Sixt products you like and add them to the shopping cart; 2. Check the product you want to purchase at Sixt; 3. Place the order, click on the Sixt Voucher Codes you got on the checkout page. Select the Sixt Discount Codes you want to use and just complete the payment.