You have to buy it in a shop
kecleon shop
Any Pokemon that has an evolution can evolve. Some Pokemon may need some sort of item like a Thunderstone to evolve, though.
wonder mail
No, there is no requirement to use a Thunderstone in Pokémon Mystery Dungeon Explorers of Darkness. It is an optional item that can be used to evolve certain Electric-type Pokémon.
i do not have explorers of sky
receive a thunderstone and when it asks if you want to use anitem say "yes" and then choose thunderstone
The main difference between Pokemon Explorers of the Sky and Pokemon Explorers of Time is that Explorers of the Sky is an enhanced version of Explorers of Time. Explorers of the Sky includes additional features such as new storylines, characters, dungeons, and Pokemon compared to Explorers of Time.
Why are you playing explorers of sky? You should be playing the real Pokemon games.
Yes, Arceus and Shaymin are both featured in Pokemon Explorers of Sky.
The sky stairway
Unfortunately you can get Arceus in Explorers of sky :/ The closest you get to seeing it is a statue...
You have to evolve it from Eevee. If there is a thunderstone in that game, use the thunderstone and Eevee will turn into Jolteon. If there is no thunderstone, then you must evolve Eevee by training it, but it might turn into Flareon or whatever the water pokemon's name is that it turns into. You can also trade it with yourself to a game that has a thunderstone and evolve Eevee that way, then trade it back.