Okay kiddo, have you ever played a video game or watched a cartoon where there are characters that look like real people or animals, but they're not actually real? Those characters are usually made using something called "computer-generated imagery," or "CGI" for short. One type of CGI is making 3D models, which are like digital sculptures of these pretend characters.
Suzanne is a specific 3D model that was created a long time ago as an example for people who want to learn how to make 3D models. She's named after a Blender developer's pet monkey! Suzanne is a simple model with a round head, big eyes, and a smile. People like to use her to practice making different shapes and textures, and sometimes she even shows up in movies or video games as a little Easter egg.
So basically, Suzanne is a pretend character that people use to learn how to create other pretend characters or things in 3D. Cool, right?