Short answers, pulled from the story.
Edgar Rice Burroughs created John Carter, writing the original story between July and the 28th of September 1911. It was first published as a serialized story titled Under the Moons of Mars in the pulp magazine The All-Story from February to July 1912.
The first novel is A Princess of Mars. It was published in hardcover in October 1917 by A.C. McClurg and Company, having been retitled from its original magazine serialization title Under the Moons of Mars.
Carter is transported to Mars by a form of astral projection while hiding from Apaches in a cave in Arizona. He later masters the process and travels between Earth and Mars on multiple occasions, with his earthly body resting in a special tomb during his absences.
The character of John Carter is in the public domain. However, the Edgar Rice Burroughs estate maintains ownership over certain specific aspects of the character.
Buck Rogers, Flash Gordon, Superman, Adam Strange, Dune, and Star Wars are among the works cited as influenced by John Carter. James Cameron also named the Edgar Rice Burroughs Barsoom stories as a direct inspiration for Avatar.
Taylor Kitsch played John Carter in the 2012 Disney film adaptation, with Lynn Collins in the role of Dejah Thoris. The film was released in the 101st year after the character's first appearance in print.