In League of Legends, players can use two types of currency: Riot Points (RP) and Blue Essence (BE). RP is obtained by purchasing them using real-life money and is used to buy items like skins or battle passes. BE is earned through missions or disenchanting champions and can be used to purchase additional rune pages or champions.
While RP is more difficult to get because it requires you to spend real-world money, BE is easy to obtain, and all you need to do to earn it is play the game.