This is a ship card like a credit card containing all the information about your order.
This card is reusable and refillable not like the current ticket who can only be used once.
For the price of 8€, you only pay once the shipping cost (25 €).
Indeed, you can if you wish reload this card the following year from your computer. You need to return to your customer account and give the serial card number without any charges. You simply pay the price of your entry.
After purchasing your tickets, you will receive an e-mail with the location of your seats(except Bronze zone) that you will need to take with you during the GP.