Content moderation is like making sure everything that's posted online is okay for everyone to see. Imagine you have a toy box with a lot of toys in it. Some of these toys could be dangerous or scary for other children. That's why you need someone to check the toy box to make sure all the toys are safe and won't hurt anyone.
On the internet, people can post things like pictures, videos, and comments. Some of these things are okay, but some of them can be mean or scary. Content moderators look at all these things to make sure they are okay for everyone to see. They check for things like bad words, violence, and inappropriate pictures.
If a post or video isn't okay, the moderators can take it down so it won't be seen by other people. It's like taking a toy out of the toy box that's not safe for everyone to play with. With content moderation, we can make sure that everything we see online is appropriate and can be enjoyed by everyone.