In free-to-play games there is usually a stamina system in place to gate progression. In Genshin Impact it is called Resin and unlike other games with a stamina system you are not gated from playing the game. What it does do is restrict how many dungeons or bosses you can loot on a daily basis. You can only restore your Resin up to 6 times a day using Primogems, a currency you acquire just by playing the game.
