I am planning to get enough Meltan candies to evolve it into Melmetal, transfer it to Sword, and train it in EV's. Do Pokemon earn EV's in Go? And if so, in what way? Because I am hoping it would be a "blank sheet" for EV training so that is easier for me.
The Bulbapedia page on Pokemon GO does not mention EVs at all. Therefore, it's safe to assume that EVs are not currently part of GO. However, even if they were, you could easily erase any EVs gained by using EV-reducing Berries in Sword. Or, if you have the Isle of Armor, there is an NPC that completely erases any EVs your Pokemon have gained.
Hope I helped!