What is the difference between Windows virtual memory and RAM ?

What does Windows virtual memory do ? How is virtual memory different from RAM memory ?

Virtual memory supplements a PC's RAM memory. When PC runs low on RAM or when there is not enough RAM available, Windows use the disk space to supplement RAM.

RAM is better than virtual memory, because it is faster (has a higher read / write speed).

If you have an SSD disk, the reading and writing speed is higher than in case of HDD.

But the reading/ writing speed of RAM is much higher than in case of SSD.