Short answers, pulled from the story.
Superman first appeared in the first issue of Action Comics on the 18th of April 1938. This publication date marks the official launch of the character who would change the landscape of American pop culture forever.
Jerry Siegel and Joe Shuster created Superman while Siegel was a high school student in Cleveland and Shuster was his friend who provided illustrations. They developed the character through multiple prototypes before selling the rights to DC Comics in 1938.
In the final version, Superman is an alien named Kal-El sent from the exploding planet Krypton to Earth. He landed near Smallville, Kansas, where he was adopted by farmers Jonathan and Martha Kent and raised as Clark Kent.
Jerry Siegel and Joe Shuster gave away the copyright to Superman for free in a contract dated the 1st of March 1938. DC Comics paid them $130 for their first Superman story but did not pay them for the copyright itself.
Superman's first appearance in Action Comics #1 is due to enter the US public domain on the 1st of January 2034. This will only apply to the character as he is depicted in 1938 while DC Comics retains trademarks on his name and image.
Bud Collyer voiced Superman in the radio series The Adventures of Superman which ran from 1940 to 1951. Collyer also voiced the character in animated shorts produced by Fleischer/Famous Studios released between 1941 and 1943.