In addition to the regular colorful cards from 0 to 9 in the uno online, you also need to know some of the following functional cards:

Draw 2 cards (Draw +2): You can play classic games this card when your opponent plays cards of the same color, or +2 in stacking rules. When you play this card the next player will have to draw 2 more cards from the draw.

Wild draw 4 cards (Draw +4): The most powerful card, you can use this card to make the next player draw 4 more cards and choose the color for the next turn.

Skip cards: You can play this card if the same color or the same type of card loses the turn, when you hit the next person will lose the turn.