Let's Go!

As with prior Pokémon games, you have the ability to have your Pokémon exploring with you out in the field. However, with this game, you have the ability to send the Pokémon out on its own in a direction set by you. Doing this, it will find various items for you, as well as even participate in battles with wild Pokémon and even some trainers

When sent out in Let's Go! mode, the Pokémon will sometimes see a wild Pokémon in the field and it will challenge it to a battle. You don't need to interact with the battle as it's going on, allowing for you to look for items and progress in the interim. Defeating Pokémon in Auto Battle earns items and experience points. It will not earn EVs

The Pokémon in Let's Go mode will not attack any Shiny Pokémon or any Pokémon with a special Tera Type.