How to evolve Onix into Steelix in Pokémon Legends: Arceus

gamepur.com:

Onix is one of the Pokémon from the original games, and you’ll be able to catch it in Pokémon Legends: Arceus. It’s a massive Rock and Ground-type Pokémon, and if you’re looking for a powerful Rock and Ground-type added to your team, we highly recommend it. But we also think you should evolve it into Steelix, its second form. To do this, you’ll need a specific item to evolve it. In this guide, we’ll cover how to evolve Onix into Steelix in Pokémon Legends: Arceus.

The only way to evolve Onix into Steelix is if you give it Metal Coat. Metal Coat is a evolution item that you can acquire in the game. There are several ways to get it, but the best way to get Metal Coat is to head over to the Trading Outpost and speak with Simona. She’ll offer to sell you several items there, such as the Metal Coat for Merit Points. You can earn Merit Points by collecting lost Satchels you find in your games. These belong to players, and they lost them when they fainted with a Pokémon attacking them while exploring Hisui.

The other way to earn a Metal Coat is to have a Ursaluna seek it out as a treasure or find one during a space-time distortion. Unfortunately, both of these methods are random.

Once you have the Metal Coat, all you have to do is give it Onix, and it will evolve into Steelix.