A rag joint is a part that connects the steering shaft (the part that helps turn the wheels) to the steering gear (the part that helps steer the car). It looks like a bunch of soft pieces of fabric (like rags) stuck together in a circle.
The reason it looks like this is because it needs to move and twist with the steering shaft and gear, so it needs to be flexible.
Imagine if you were playing with a toy car and the wheels turned when you turned the steering wheel. The steering shaft and gear would need to be connected, and that's where the rag joint comes in.
It keeps the steering system working properly and allows the driver to easily turn the wheels. So, it's pretty important!