The color is a characteristic that can be easily recognized by sight, however, each Pokémon's color was made official with Pokémon Ruby and Sapphire, where, in the Pokédex, you can arrage Pokémon by this distinction.
Each Pokémon is classified under one color, even though it has more than one color in its body. In most cases, the Pokémon's color is the one that predominates over its body. It the Pokémon has multiple forms, each form has its own color and may be categorized under a different color if it radically changes the colors of its body. Shiny Pokémon do not have their own colors.
The colors used for the classification are red, blue, yellow, green, black, brown, purple, gray, white and pink.