On your Nintendo Switch, open Animal Crossing.
Travel down to the bottom half of your island and enter Dodo’s Airlines.
Talk to Orville at the Dodo’s Airlines desk.

Note:
ChoosingI wanna flyallows you to visit other people’s islands.
Choose to invite friends via local play or via online play.
Choose to inviteAll my friendsorInvite via Dodo Code.

InviteAll my friendsopens your village to anyone on your friends' list.
The friends you’ve invited can now wander around your island, allowing you to interact with them.
That also means you could add them as one of your Animal Crossing best friends.

Be careful as to who you add as a best friend within the game.
On Animal Crossing, open your Nook Phone by tapping ZL.
Choose a name from the list to add.

TapAsk to Be Best Friends.
Once they’ve accepted your invite, they can explore your island and do whatever they want.
you’re able to also message them regularly.

Ideally, you’ll need your friend’s Nintendo Switch code to do so.
However, you’re able to search through other methods.
On your Nintendo Switch, tap your user profile picture.

TapSearch with Friend Code.
key in your friend’s code.
you might also tapFriend Suggestionsif you’ve connected your Nintendo Switch to social media accounts.

This method allows you to find friends that have done similar.
Send the friend request and wait for them to accept it.
Once accepted, you’re able to now invite them more easily within Animal Crossing.
FAQ
you might’t add someone as a friend in Animal Crossing until they visit your island.
To remove friends on Nintendo Switch, go to your userprofile picture>Friend List.
Choose a friend, then selectOptions>RemoveorBlock.
To trade items, open your inventory, choose an item, and selectDrop Item.
The other player can do the same, and then you both can pick up the items you dropped.