Cards can be played to accomplish a variety of tasks, such as gaining additional armies, spying on opponents, airlifting armies around, etc.
 Receiving Cards
When you successfully attack and capture an enemy or neutral territory, at the end of that turn you will receive a piece of a card, regardless of whether you lose the territory later that turn. You can't get more, no matter how many territories you take.
Games can also be configured to give more than one piece per turn via the number of card pieces per turn setting. In this case, players who take a territory will always get exactly that number of pieces configured by that game each turn.
If a game has multiple types of cards included, the type of card(s) you get is determined randomly based on their weight. It's also possible for game creators to configure minimums that remove the randomness, either partially or completely.
The game creator can pick which cards will be available in their game, so be sure to check the game settings to know which types of cards you're dealing with.
Cards can be divided into any number of pieces. You cannot play a card until you have collected the entire card.
You may only hold onto a certain number of cards at one time, as defined by the maximum number of cards you can hold setting. Therefore, there can be occurrences where you must use or discard a card.
When you play a card, that card is consumed. Even if the card had no effect, you don't get your card back. For example, if you spy on a player who gets eliminated the same turn, the card is just wasted.
 Types of Cards
Warzone has 13 different cards (not counting mods):
- Reinforcement Card
- Spy, Reconnaissance, and Surveillance Cards
- Blockade and Emergency Blockade Cards
- Order Priority Card
- Order Delay Card
- Airlift Card
- Gift Card
- Diplomacy Card
- Sanctions Card
- Bomb Card
 Card Fog
There are two "fog" settings that determine what is shown to your opponents in regards to cards:
- Visibility of opponent's cards: This setting, visible or hidden, determines whether you can see what cards your opponent is holding as well as the type of card they get at the end of each turn. To see the cards, open the Cards panel and select a player in the drop-down.
- Visibility of opponents playing cards: This setting, visible or hidden, determines whether you can see when your opponents play their cards. If it's set to visible, then all cards being played are public (they'll show up in the orders list.)