I remember wondering about the difference when I was a kid. I thought they looked like the same thing, but I figured magma was just a cooler name (no pun indented) for lava. The truth is a bit more technical, but still fun to know =)

Have a little extra read about lava and magma if you like:

https://www.nationalgeographic.com/science/article/volcano-magma-lava-difference-science (last accessed 09.04.2021)