A new variant Pokémon in Sword is an Ice-type of Black and White’s Darumaka and Darmanitan. The evolution process is a little different to Black and White, however, as you will need an Ice Stone to be able to make Darumaka evolve into Darmanitan.
To find the Ice Stone, you can either try your luck at this wonderful spot at the Lake of Outrage, or you can make your way to Route 9. You will need a Roton bike with the Surf feature to get either of them, and Route 9 will give you a guaranteed Ice Stone, while the Lake of Outrage method can be down to the luck of the draw.
To find the Ice Stone on Route 9, just cycle down into the water, then go toward the upper right corner and follow that path around until you see something shining in the water. That will be an Ice Stone.
Once you have the Ice Stone, you can use it on Darumaka and evolve them into Darmanitan. You don’t need to worry about leveling them up, there is no level requirement for the evolution to occur.
If you need more help with Pokémon Sword and Shield, we have a range of guides that you might find useful. From how to use the PC Box Link, how to change a Pokemon’s nature, and how to trade Pokémon. If you are looking for some of the rarer Pokémon, we can show you where to find Dreepy and Ditto, as well.