By using an Evolution Stone:
* Vaporeon: Use a Water Stone
* Jolteon: Use a Thunder Stone
* Flareon: Use a Fire Stone
* Espeon: Level up Eevee with high friendship during the day.
* Umbreon: Level up Eevee with high friendship during the night.
By using a special method:
* Leafeon: Level up Eevee near a Moss Rock
* Glaceon: Level up Eevee near an Ice Rock
* Sylveon: Level up Eevee with high friendship and knowing a Fairy-type move.
Friendship Level: Friendship levels up by battling with Eevee in your party, feeding it berries, and using certain items like the "Soothe Bell." You can check your Eevee's friendship level in the "Summary" screen in the game.
Important Notes:
* You can only evolve Eevee into one of these forms once.
* Some methods, like the ones involving evolution stones, may require a specific level for Eevee.
* In certain games, like Pokémon Let's Go, you can obtain specific Eevee evolutions through specific events.
Make sure you are familiar with the specific game you are playing, as there might be slight variations in the evolution process. Have fun evolving your Eevee!