Imagine you have a nickname that you use when you play with your friends. That nickname tells your friend who you are and how to find you to play with you.
A NIC handle works in a similar way; it's like a nickname for people who work with computers and the internet. When you use the internet, you might need to tell someone your name and contact information. But instead of giving them your real name and phone number, you can give them your NIC handle.
Your NIC handle helps people find you on the internet, and it's usually made up of letters and numbers. It's important to keep your NIC handle safe and private, just like you wouldn't want to give your buddy's nickname to someone you don't trust.