Magnolia is one of the NPCs of Postknight, and also Chief Merrick’s daughter. She will not appear at the start of the game. However, upon completing routes, Chief Merrick will ask the player to find his daughter who was looking for other Pompon villagers. After that, the player will automatically give Magnolia a White Lily, and the player will be able to receive gifts from Magnolia and give gifts to Magnolia, like other NPCs.
You can check this in the Relationships page, but I’ll just put this here if you’re lazy.
White Lily (1/2)
Mushroom Soup (1/4)
Polka Dot Ribbon (1/2)
Sweet Delight (1) Blossom Festival
Pumpkin Ensemble (1) Hollow’s Eve
Wintertide Sweater (1) Wintertide Event