According to the modern versions of the Superman origin story, Superman got his powers from the rays of the yellow sun when he came to Earth. Krypton, his home world, had a red sun, and normal Kryptonians did not have super powers.
The story of how Superman got his powers has changed several times since early appearances of the Man of Steel. In his first appearance in Action Comics No. 1 and in the first newspaper comic strips, Superman and all Kryptonians, because they are evolutionarily advanced, had super powers. With the appearance of Superboy in the mid-1940s, the story changed and attributed Superman's powers to the fact that the planet of Krypton had a much greater gravitational pull. Once he was free from Krypton's gravity, his strength and all of his other powers increased. The first explanation that Earth's yellow sun was what gave Superman his powers was in March 1960 in Action Comics No. 262. Since then, through various comic, television and film series, the yellow sun explanation has prevailed.
Superman's powers also varied with the passage of time. In the beginning, he possessed the basics of super strength, super speed and invulnerability. Later, writers added X-ray vision, super hearing, superhuman breath, flight, genius-level intellect and longevity. In recent decades, writers of Superman comics have curtailed his powers through various disasters to make it easier to come up with dangerous situations that challenge him.