You can find the following currencies in Mythic Legends:
Coins - the standard currency in the game. They can be earned by opening chests, completing daily challenges, or progressing on the Battle Pass. Coins can be used to upgrade Champions and Legends, and unlock new ones as well.
Gems - the premium currency that can be purchased in the shop. You can also earn extra gems via daily challenges or progressing on the Battle Pass. Gems can be used to purchase coins, chests, Champion and Legend cards, or for rerolling artifacts.