It is necessary to get involved in a mission called "Food from afar", during our work here we get Kamisato Ayaka to give us the object, only that before that it will be necessary to take charge of unlocking the mission that is usually the third quest in the history of Ayaka belonging to to Act I Whispers of the crane and the white rabbit.
It should be noted that Ayaka's mission is usually unlocked automatically after having completed Chapter II of the Archon Quest, Act I The Immovable God and Eternal Euthymia, once we conclude the chapter and Ayaka gets in touch with us for a personal matter, we will receive the white heron hairpin.
This is all we can tell you about how to get the white heron hairpin, it will only be necessary to get involved in an additional mission in Genshin Imoact.