Okay kiddo, so when you see an ad on TV, the internet, or maybe even on a billboard, the company that made the ad wants you to buy their product or service. Sometimes, they might not tell you the whole truth about what their product or service can do. They might exaggerate, or make things up completely. This is called "misleading advertising".
It's like if someone told you they had a magic toy that would make you fly, but when you got it, you realized it was just a regular toy that didn't actually do anything special. That person would be misleading you.
The reason companies do this is because they want to make as much money as possible. If they can convince you to buy their product or service, they can make a profit. But it's not fair to you, because if you believe their misleading advertising, you might end up wasting your money on something that doesn't actually do what you thought it would.
That's why it's important to be a smart shopper and do your research before you buy something. Don't just believe everything you see in ads! And if you think a company is being really dishonest, you can report them to a special organization called the Federal Trade Commission.