https://www.gamespot.com/articles/pokemon-go-adds-more-alolan-forms-heres-how-to-get/1100-6459983/

Niantic has rolled out a big new update for Pokemon Go, which finally implements two commonly requested features--trading and friends lists--to the mobile game. On top of allowing players to send Pokemon and items to each other, the update introduces several new Alolan Pokemon, which can only be obtained through the gifting feature.

As its name suggests, the gifting feature allows players to give and receive special Gifts. These are collected by spinning PokeStop discs and can be sent to other players on your friends list (they can't be opened by the player who first obtained them). The Gifts include "a stash of helpful items," among them new 7 km Eggs, which will hatch into the Alolan form of a Kanto Pokemon.