Delegation is like when you ask someone else to help you with something. It's like when mommy and daddy ask you to clean up your toys before bed but they leave it up to your big brother or sister to make sure you actually do it.
In the grown-up world, delegation happens when someone in charge, like a boss, asks someone else to complete a task or make a decision for them. They trust the other person to do a good job and usually give them instructions on what specifically needs to be done.
So, delegation means you're giving someone else some responsibility to help you out, and you have to trust that they'll do a good job. It's important because it helps spread the work out among a team or group, and it helps everyone get things done faster and better.