In order to evolve Eevee into Leafeon and Glaceon you’ll have to get specific items: either the Glacial Lure Module for Glaceon or the Mossy Lure Module for Leafeon, both of which can be purchased in the in-game shop for 200 coins each. Grass-type Leafeon and Ice-type Glaceon are the latest Eeveelutions to be added to Pokémon Go and unlike Vaporeon, Jolteon and Flareon there is a secondary way of securing their forms. You can purchase both Lure Modules needed to evolve to Leafeon or Glaceon from the in-game shop. Eevee evolutions in Pokémon Go: How to evolve into Jolteon, Vaporeon, and Flareon So, once you’ve evolved an Eevee into each of the available evolutions using this method then you’ll need to start resorting to other means if you want any more. Something important to note with this method for Eevee evolutions in Pokémon Go, though, is that it only works once for each nickname. If you really hate giving your Pokémon nicknames, you can always change it back after your Eevee has evolved. With this method, all you have to do is rename your Eevee with one of the names below and then, when you get the requisite 25 candies to evolve it, everything will fall into place.
The classic means of getting the Eevee evolutions in Pokémon Go that your heart desires is to give them each a specific nickname before they evolve.