huss97ein, that's not how evolution works. Evolution takes thousands, often millions of years. Pokémon evolve spontaneously. A better way of describing Pokémon evolution is a baby Pokémon becoming an adult.
For example, you have a Caterpillar Pokémon which becomes a butterfly (this is not like real world evolution):
For example, you have a Caterpillar Pokémon which becomes a butterfly (this is not like real world evolution):