A parachute descends slowly whereas a stone dropped from the same height falls rapidly, because

Gravity is pulling the man down while friction with the air slows him down. With the parachute out it adds more friction slowing him down because air resistance works against the very large surface area of the parachute. A free falling skydiver that has not yet opened his parachute can make his downward speed vary between about 110 mph and 225 mph using air resistance. A spread eagled position presents the maximum area, and we fall the slowest.