Galarian Slowpoke and Slowbro are the latest regional forms added to Pokémon Sword and Shield, as part of the recent Isle of Armor expansion. You'll have no trouble catching yourself a Slowpoke – they're all over the island – but getting its evolved form takes a bit more work. Here's how to evolve Galarian Slowpoke!
Find the right materials
While Kantonian Slowpoke is able to evolve into Slowbro by leveling up, his Galarian form requires the Galarica Cuff item, which must be specially crafted. For this, you will need Galarica Twigs, which appear as glittery objects under the various trees on the Isle of Armor. Check these locations as often as possible, as you will need 8 of these items to get a Galarica Sleeve. Next, bring your collection of twigs to the small island southwest of the Isle of Armor (marked with red arrows on the map above), in the training sea near where you arrived for the first time on the island. The girl you'll meet here will make you a Galarica Cuff from the twigs you've collected.
Slow evolution
Use the Galarica Cuff on Slowpoke and it will immediately evolve into Slowbro, learning Galarian Slowbro's signature Shell Side Arm move in the process. This is a particularly useful poison-type attack, having unusually high damage for a poison-type move as well as the ability to poison the enemy. Not only that, it will turn into a physical or special move depending on which one does the most damage. This is the only move available with this property so far, letting you benefit from Galarian Slowbro's Attack and Special Attack stats. Unfortunately, it will be yet another before you can evolve a Galarian Slowpoke into a Slowking - the items needed for this evolution won't be available until the Crown Tundra expansion releases later this year. If you're looking for Kantonian Slowpoke, Slowbro, and Slowking instead, you can get a classic Slowpoke from Trainer Diglett on the Isle of Armor after saving a few of his Digletts.