What is an NFT code?

Excuse me, could you please explain what an NFT code is? I've been hearing a lot about it recently, but I'm still a bit hazy on the concept. I understand it has something to do with cryptocurrency and digital assets, but I'm not quite sure how it works or what its practical applications might be. Could you break it down for me in simple terms? Maybe give me an example or two to illustrate its usage? I'm really curious to learn more about this emerging technology.