How to Change the Variables of an Instantiated Object?

I tried looking up ways of doing this but most were in JavaScript and I got confused, I basically am trying to make a Binding of Isaac game where you shoot in 4 directions with the camera tilted down above the player. I am trying to make it so whenever I shoot a projectile, the clone will have some kind of variable telling it if I pressed up down left or right. I was going to make 4 separate prefabs for each but that would be messy and I want to learn more. thanks