Evolution is used to make your Pokemon more powerful so it can engage in battles and help you succeed on your journey. Most Pokemon have three evolutions, the third one of course being the strongest. Some Pokemon have two evolutions, the second being powerful. Instead having a second evolution in the middle, the Pokemon will go straight from weak to more powerful. There are however some that have no evolution, they just stay the same. Of course legendaries do not evolve, they're already too powerful! But normal Pokemon like Shuckle or Relicanth have no evolution, but they still put up a good match in battle.
There is one Pokemon known as Eevee that lives and breaths evolution, quite literally, really! Eevee can evolve into seven different Pokemon, but only one can be chosen.
If you give Eevee a thunderstone, it will evolve into the electric type Pokemon Jolteon. Jolteon has powerful attacks and is quite fast. If you give Eevee a waterstone it will evolve into the water type Pokemon Vaporeon. Vaporeon hits great but not as hard as some of the other Eevee evolutions. Vaporeon is rather bulky and can take some hard hits. If you give Eevee a firestone, it'll evolve into the fire type Pokemon named Flareon. Flareon can hit hard, but is really neutral all around for attacks and being bulky, all being the same not more powerful or not bulky, just in the middle.
If your Eevee and you have great friendship during the day it will evolve into the psychic type Pokemon named Espeon. Espeon has great special attack, much like Jolteon, just not as fast. If Eevee and you have great friendship during the night it will evolve into the dark type Pokemon Umbreon. Umbreon is very bulky, much like Vaporeon but can still manage to hit pretty good. If your Eevee levels up by the Moss Rock, it'll evolve into the grass type Pokemon Leafeon. Leafeon has good attack, but a bit weak when it comes down to defenses. If your Eevee levels up at the Ice Rock, it will evolve into the ice type Pokemon, Glaceon. Glaceon has great special attack just like Jolteon and Espeon. Evolution is used to power up Pokemon, and Eevee knows what evolution is for sure! On the journey to becoming a Pokemon Master, Eevee is a great choice seeing you can evolve it to any of the stated evolutions. What Eevee evolution is your favorite?