Anju is a recurring character in the Legend of Zelda series. She she plays a different role in each game she appears.
Ocarina of Time
In The Legend of Zelda: Ocarina of Time, Anju is a cucco keeper. This causes problems for her as she is also allergic to cuccos. When her cuccos escape, she relies on Link to round them up for her.
In The Legend of Zelda: Majora's Mask, she works at the Stock Pot Inn and is engaged to be married to Kafei. However, she becomes concerned when Kafei mysteriously disappears. Unbeknownst to her, her fiance had been transformed into a child by the Skull Kid possessed by Majora's Mask, and subsequently, the Sun's Mask that symbolizes his love for her is stolen by the thief Sakon. Link helps him retrieve the mask from Sakon, and then Kafei finally rejoins Anju. After Link destroys Majora's Mask and saves Termina, Kafei is restored to adulthood, and he and Anju marry.
The Minish Cap
In The Legend of Zelda: The Minish Cap, she is again a cucco keeper, and requests Link's help in rounding up her cuccos.