Okay kiddo, have you ever seen a big mountain with a flat top at the peak? That's kind of what a volcanic plateau looks like.
When a volcano erupts, it's like a big explosion from the earth. Lots of melted rock, ash, and gas shoot up into the air. This stuff is super hot and it cools down as it comes down.
After a long time of this, the cooled down rock and ash starts to pile up and form a flat area around the volcano. Some volcanic plateaus can be hundreds of miles wide!
So think of it like a big pancake that was made from the explosion of a volcano. Even though it's flat on top, there's still a lot of volcanic rock and ash underneath that makes it very different from a regular mountain.
But remember, volcanoes can still erupt from these plateaus, so it's important to be careful around them!