Question

In which episode does charmander evolve?

Answer 1

Ash's Charmander?

It evolved into Charmeleon in March of the Exegguror Squad.
It then evolved into Charizard in Attack of the Prehistoric Pokemon.

Source

Answer 2

Ash's Charmander evolved into Charmeleon in March of the Exeggutor Squad. It quickly grew unruly and disobedient and evolved into Charizard soon after, in Attack of the Prehistoric Pokémon.

Source: Bulbapedia