About Top Eleven Gift Cards
Game Cards are a way to receive Tokens, Health Packs or ingame cash, depending on the code. Codes will be used in promotional campaigns, competitions, when purchasing certain products (for example, like how you can redeem codes from Pepsi products in Turkey at the moment) and as purchasable gifts (you buy a code and send it to your friend as a gift card, for example).
Codes from game cards can be redeemed here. You will then be able to enter the code and click "Redeem" to use it. The official site contains a "Redeem code" tab in the game, which functions the same way as the one on Facebook.
Redeeming a Gift Card
Mobile users can redeem codes as well. By clicking any of the Health Pack, Token or Cashicoins, they will be taken to a purchase screen for those items. That screen will also have a Redeem tab in which they can enter a code.
Screenshots with redeeming gift card: