I just want to post but for some reason people keep targetting the criticism on these specific things.
Go into the summary screen of a Pokémon and go to the moves and stats page. Click the L button and it'll bring up your Pokémon's EVs. Unfortunately, it is impossible to view exact EV's in-game. You can only tell if an EV is maxed out, as the stat will sparkle while using the judge function.
It is possible to figure out a Pokémon's EV's by using a stat calculator, but this requires knowledge of a Pokemon's IVs which are also not viewable in game. If you're training a Pokémon for competitive, you could use bottle caps to max out a Pokémon's IV's. You'll then know it's IVs are 31 and be able to determine the EV's based on that.