Shiny refers to a rare body color of Pokémon. In Pokémon, Pokémon have more than one in eight thousand chances that they will appear different from ordinary Pokémon when they are spawned. Each type of Pokémon only corresponds to one shiny color.
Shiny Pokémon is a rare variant of Pokémon, and its color is different from other Pokémon of the same kind. You may encounter Shiny Pokémon randomly in the wild, especially at special events such as Community Day or Pokémon GO Fest. We can also buy Cheap Shiny Pokemon, this is the very fast way.
The Shiny Pokémon have no advantage in the battle. They are purely rare. The judgment of the Shiny is completely independent of the judgment of the Pokémon's character and individual value, so there is no saying that the Shiny Pokemon are stronger than Non-Shiny.
Another thing to note is that the regional form of some Pokémon may also be shiny. Just like standard Pokémon, if there is a shiny icon above the CP, you can judge whether they are shiny.