The official Pokémon website has announced that players of Pokémon Sword or Pokémon Shield that transfer one or more Pokémon between those games and the Nintendo Switch version of Pokémon HOME, can receive a Grookey, Scorbunny, and Sobble.

Get Grookey, Scorbunny, and Sobble with Hidden Abilities through Pokémon HOME

Enjoy some popular Pokémon with new tricks as you get ready for your Pokémon adventures to continue.

Have you been transferring Pokémon between Pokémon Sword or Pokémon Shield and Pokémon HOME as you prepare for your adventures in The Isle of Armor? Starting Tuesday, June 2, 2020, at 6:00 a.m. PDT, if you transfer one or more Pokémon between Pokémon Sword or Pokémon Shield and the Nintendo Switch version of Pokémon HOME, you'll be able to receive a Grookey, Scorbunny, and Sobble with Hidden Abilities as Mystery Gifts in the mobile device version of Pokémon HOME.

To claim your in-game gifts, follow these steps.

1. Launch the mobile device version of Pokémon HOME, and tap the button at the bottom of the screen to open the menu.
2. Select Mystery Gifts.
3. Select Gift Box.
4. Select the gift in your Gift Box that you'd like to claim.
5. Select Claim, and the Pokémon will be deposited into your Pokémon HOME Boxes.

Note: In order to receive these Pokémon, you will need to have the Nintendo Switch version of Pokémon HOME and the mobile device version of Pokémon HOME linked to the same Nintendo Account.

Source: https://www.pokemon.com/us/pokemon-news/get-grookey-scorbunny-and-sobble-with-hidden-abilities-through-pokemon-home/