Is it possible for you to evolve an Eevee into an Umbreon with a Moonstone? Or any stone for that matter? Need a quick answer, please.

No, it cannot. Stones arent used for evolution in this game in anyway :/ there is no Umbreon or normal Espeon in this game, just a CursedEspeon.

Thanks anyways. I never really stay on long enough to train or do anything much so I was just wandering about that.

Are you saying there is no Umbreon period? Or are you saying that there aren't any normal ones (leaving cursed, shadow, etc.)?

Well, actually even in the real game a stone cant evolve an evee into umbreon.

Yeah, that's true. I was just wondering if it was possible maybe to catch a wild one or swap into one. Would we have to get an Umbreon promo? Maybe that's one way to do it.

Stones are used. The Fire, Water, and Thunder Stones are used to evolve Eevee to Flareon, Vaporeon and Jolteon. As for Dawn, Shiny and Moon Stone, I have found no use for them yet.

no it cant try it but it wont work but i wish tht was the way it worked cause i really wish there was umbreon in this game

I have tried and I have also evolved three Eevee into Jolteon, Vaporeon and Flareon with a Thunder, Water and Fire stone respectively. And Umbreon and Espeon haven't been introduced into the game yet. Neither is Leafeon and Glaceon.

the only ones that normal Evee evolves creed are in the first season (jolteo, Vaporeon and fareon)

no you cant use a moon stone there are only c.espeons in this game just keep a normal evee.

is true and I tried to evolve Evee for leafon and not of bounier I think is right because these options I saw was three

Well I dont think you can.. I've tried but it doesnt work for some apparent reason.