Pokemon, the game which isn't complete without evolving your Eevee (provided you have one) is one of the most complete pokemon. Being one of the most popular pokemon in the game, it has also a lot of evolutions than others because of its appearance that can adapt to different elements.

Eevee can evolve to suit different environments depending on user choices that wants it to better be used as water or electric or even the psychic type. The evolution of a pokemon to its better form is actually not that complex. You would need some resources to begin with.

A complete guide that's on itechpost, reveals that the required materials are independent on the conditions for an evolution to begin with. Beginning with Umbreon, it's one of the most challenging evolutions due to its conditions which require users to evolve night light. Hence, Eevee can only evolve to Umbreon during the night.

The process is the same as vaporeon which is also trickier to evolve is done by befriending Eevee to a level of 220 at the minimum which is a bit challenging. It seems like players need to feed the pokemon with a lot of berries and vitamins and also win a lot of battles with it.

Once you achieve the prerequisite, players need the Soothe Bell. Eevee will then evolve into Espeon. But however, if done in the night, the resulting evolution will be Umbreon.

Proceeding to Jolteon which is a bit more common and easy to achieve, Thunderstone is required for the evolution. According to this pocketgamer details, it can be obtained by playing minigames at Poke Pelago or purchase one in Konikoni city for 3000 credits if you have them in adequate numbers.

You can also use the same credits to evolve Eevee into Vaporeon provided you have a water stone. However, where to find an Eevee? Just head to Akala island that's the second island in your adventure!