Do you wonder how it feels when you step on Jupiter surface ? Well Jupiter is entirely composed of heavy hydrogen and helium , and some other gases. So if u step on its surface then you will be crushed to the center of the planet due to its extreme pressure.
When we look Jupiter actually we are viewing its outermost surface of its clouds. About 90% Hydrogen and 10% helium with other gases combine to form Jupiter atmosphere. The seen bands and storm on Jupiter are formed on upper atmosphere. The clouds layer that we see are composed of Ammonia which only extends down approx. 50km . The giant storm like Red spot occurs within this layer however it is believed that they dredge up material from deeper inside the giant planet.
If u could stand on its surface then you would experience extreme gravity which is 2.5x than the earth surface. suppose if u pounds 100 on earth u would be 250 pounds on Jupiter atmosphere. But the reality is there is no actual surfaces so you can’t stand on it.