Charmander is one of the starter Pokemons in the game along with Bulbasaur and Squirtle. It is a pure fire type pokemon. In the series, Ash got Charmander as an abandoned pokemon. Charmander got sick and Ash took care of it. So Charmander realized how bad its former trainer was (after hoping the trainer will come back for it) and joined Ash's team because of his kindness.
In Pokemon Go, its max CP is at 831. It can learn Ember and Scratch as fast moves while Flame Charge, Flame Burst and Flame Thrower are its charge moves. It can be obtained as well by hatching from a 2 km egg. If used as a buddy, it needs 3 km distance to get one Charmander candy.
As a fire type Pokemon, it is weak against ground, rock and water Pokemon. It is super strong, however, against bug, grass, ice and steel types. I like it because it's cute and fiery. Attack wise it is not really super strong but it is good for Pokedex entry.