Instead of walking a certain distance, you will need to make Eevee your Buddy Pokemon.
Just like with the other Eevee evolutions, check that the silhouette on the Evolve button is the correct one before tapping on it.
To evolve into Umbreon or Espeon, keep an Eevee as a buddy and walk this Eevee for 10km.
If you evolve your Eevee during the day, youll get an Espeon, if you evolve at night, youll get an Umbreon.
While it is storing this energy, its internal temperature can climb to 1600 degrees.
It is a fire type, which makes it great against grass, bug, and steel types.