You can collect cards from packs in the game.
Packs with cards can be found in the following ways:
Tournaments with card packs
Challenges with card packs
Quests with card packs
VIP Battle Pass with card packs
Offers with card packs
Store with card packs
Swapping duplicate cards for card packs
Each card pack contains cards of different rarity. The more rare the pack, the more rare the cards will be in the pack.