What is hashing for dummies?

Sure, here's a description of hashing for dummies, simulated in the tone of a questioner: "Hey, I've been hearing a lot about hashing lately, but I'm not really sure what it is. Can you explain it to me like I'm a dummy? I've heard it has something to do with cryptography and making sure data stays secure, but I'm not really clear on how it works. Is it like a secret code or something? And why is it so important in the world of cryptocurrency and finance?