Answer:
A supernova forms a great number of things. In medieval times, astronomers and scholars would occasionally notice a new star appear in the sky. Since all medieval scholars normally wrote and spoke Latin, they called them "Nova Stellarum", which is Latin for "New Star". Clever and tricky, these medieval scholars!
We now know that these are actually "old stars" in the process of dying. A "supernova" is an especially bright and powerful "old star" as it explodes. What does it form? Everything around us! The great mass of all matter in the universe is hydrogen gas, the simplest element. In the core of a star, hydrogen fuses into helium, the second most common element. And that's all there is; hydrogen and helium, from one end of the early universe to the other.
But toward the end of their short lives, very massive stars begin to collapse, and the pressure and temperature of the stellar core shoots up. In that extreme environment, the helium itself can fuse into carbon, and can form oxygen and nitrogen and other light elements. Only during the last few moments of a star's existence, when the pressures and temperatures reach a peak, can even more massive elements be forced to fuse - creating all of the heavier elements like iron, or lead, or gold. Once the star begins fusing iron into really heavy elements, the star explodes and destroys itself in a titanic supernova explosion.
Some of the mass, the heavy elements, are blasted back into space, where they drift in space for eons until they fall into a stellar nebula, and become part of a new solar system. In fact, every atom of iron in the hemoglobin of your blood was formed in the core of a star dying in the explosion of a supernova many billions of years ago!
The mass of the star that wasn't blasted back into space is crushed into the core of the star, where it forms either a neutron star or a black hole, depending on the mass of the original star and how the explosion proceeded.
Our Sun, an entirely average star, is too small to become a nova or supernova.