A riser card is like a magical elevator for your computer. Imagine your computer is a tall building with many floors. Some of the important parts that help it work properly are located at the bottom floor (motherboard) and they need to be connected to other parts that are on the higher floors like the graphics card or audio card.
But how do you connect them when they are so far apart? That's where the riser card comes in to save the day! It's basically a tiny platform that sits on the motherboard and it provides a way for these far away parts to connect with the motherboard by lifting them up and bringing them closer.
It's like building a tower of blocks and using a special piece to connect the two different levels. And just like that magic piece, the riser card connects the different parts of your computer and helps it work better!