Pokemon Go - Special Evolution - Eevee

By naming your Eevee before you evolve it you can choose which form it transforms into. Be aware that this only works for the first time an Eevee evolves into each type.

Rename Eevee as Rainer to evolve into Vaporean

Rename Eevee as Sparky to evolve into Jolteon

Rename Eevee as Pyro to evolve into Flareon

Rename Eevee as Sakura to evolve into Espeon

You can also get Espeon by walking 10km with Eevee as a Buddy and evolving during the day.

Rename Eevee as Tamao to evolve into Umbreon

You can also get Umbreaon by walking 10km with Eevee as a Buddy and evolving during the night.

Rename Eevee as Linnea to evolve into Leafeon

You can also get Leafeon by evolving an Eevee when in range of a PokeStop with the Mossy Lure.

Rename Eevee as Rea to evolve into Glaceon

You can also get Glaceon by evolving a Glaceon when in range of a PokeStop with the Glacial Lure.

Rename Eevee as Kira to evolve into Sylveon

Eevee can also be elvolved into Sylveon by earning 70 buddy hearts with it.