Question: how to evolve eevee into all forms?
Answer: Rename Eevee as Tamao to evolve into dark-type Umbreon. Rename Eevee as Rainer to evolve into water-type Vaporeon. Rename Eevee as Sparky to evolve into lightning-type Jolteon. Rename Eevee as Pyro to evolve into fire-type Flareon.