So Genshin Impact uses a "gacha" system for earning new characters and some powerful weapons, which essentially means you can buy loot boxes for a slight edge. It sounds concerning, but you'll also earn plenty of loot and the currency needed to buy these loot boxes just for playing.
These loot boxes are called Wishes. Some are seasonal, others are always the same, but you should always save your Wishes and spend them in groups of 10. The reason being is that when you open 10 at once, you're always guaranteed a four-star weapon or character, which is the second highest tier available. The drop rate for four-star rewards is a measly 5 percent, so take what you can get. (Five-star rewards only have a 0.6 percent chance to drop. Yikes.)