There is a key difference between the Olympics and the Paralympics, where in the Olympics the participants will be able-bodied people and whereas in Paralympics the participants will have some form of physical or intellectual disabilities.
Paralympics was originally started as a way to help soldiers who had been wounded in World War II.
Paralympic games were started off as a way to provide rehabilitating sport for veterans, which was eventually turned into recreational sport by having a friendly competition before eventually developing into Paralympics, what is called today.
Paralympics is overseen by the International Paralympic Committee (IPC) whereas the Olympics are overseen by the International Olympic Committee (IOC).
As Summer Olympics and the Winter Olympics, similarly their are Summer Paralympics and the Winter Paralympics. However, both the Olympics and the Paralympics take place every four years, in two segments.
Due to a joint agreement between IOC and IPC, the Summer Paralympics take place in the same city as the Summer Olympics, immediately after the Olympics has concluded. Similarly, the Winter Paralympics take place in the same city after the Winter Olympics.
The first modern Olympics took place in 1896, whereas the Paralympics first officially took place in 1960. And yes, the Olympics are much older and are much more popular than the Paralympics.
There is a large funding gap between the Olympics and Paralympic athletes, which has caused the Paralympians to strive for treatment equal to non-disabled Olympic athletes. Something that is an ongoing struggle, but Paralympians have now been getting more attention than they previously were.
And Paralympics is the Second biggest sporting event in the world after the Olympics.