[Charmander → Charmeleon → Charizard]
Charizard is the third evolution of Charmander. Charmanders have NEVER been available in the wild to catch.
Charmander is a starter Pokemon of the popular first generation games: Pokemon Red, Blue and Green (Japan) and the remakes of those games: Fire Red and Leaf Green.
Prof. Oak gives you the chance to choose a starter from 3 different types of Pokemon:
Squirtle (water), Charmander (Fire), and Bulbasaur (grass)
You choose one, if you happen to choose Charmander he will evolve into a Charmeleon at level 16, and into Charizard at level 36. There is a whole page dedicated to Charmander, their evolutions and their attacks here:
An exception to this rule appeared in Pokemon Yellow where your starter happens to be Pikachu. In that particular version of first generation Pokemon games, you had to acquire Charmander in Cinnabar Island.