For players who want to prevent their Pokémon from evolving, they have a few methods available to them in Pokémon Sword and Shield. A straightforward way to stop the Pokémon from evolving is to give it the Everstone, which works on any Pokémon holding it. You have the opportunity to acquire it exceptionally early.
You can find it during the first portion of the game in Turffield, where you fight the first Pokémon Gym leader. When you’re there, starting at the Pokémon Center, go to the right, and proceed down the path until you can take your first left. It’s down a minor incline with wooden stakes on either side. Head down, and then take the next first left you have available to you.
You should arrive at a dead end to find a shiny speck, which should be the Everstone. This location is where you can find the first one at the earliest time.
Luckily, there are locations you can start farming an Everstone for multiple Pokémon to hold during your adventures. The only other place in the game is in Bridge Field, in the Wild Area. You need to locate the Digging Duo, who are right next to the Nursery to the east side of the map. Walk up to them and pay them 500 Watts to dig for you. They have a chance to discover an Everstone during their search.