All of the characters in Genshin Impact have elements they can use in battle, as do the enemies you fight in the game. Some of them might be frozen, others might be wet, and some enemies have the power to shock you using electricity. You can optimize your character’s elements, and the elements of an enemy, by causing an elemental reaction.
You need to cause an elemental reaction with two specific elements. For example, if there is an enemy that has “hydro” or is “wet,” you can hit them with a ‘”cryo” attack. When hitting an enemy using those two elements, you cause them to freeze, and they will be unable to move for a short time, making it easy for you to swiftly attack them and potentially take them out. The same goes for using the element Geo on anything with Cryo, Electro, Hydro, or Pyro on it, causing the object to Crystallize. The more elements you attempt to combine in Genshin Impact, the more elemental reactions you can learn about.
Some of the elements cancel each other out. For example, if an enemy has Pyro and you attempt to hit them with Hydro, the Pyro effects will go away, causing Vaporize to happen. You want to make sure you don’t put out a fire you created to destroy an enemy’s shield or to cause damage over time to a stronger foe.
It’s a good idea to hit an enemy with a particular element from one of your characters and then switch to another that can exploit it during the battle. Changing characters is pretty simple, and a worthwhile endeavor to do more damage in Genshin Impact.