How can the three-year-old daughter of a Muslim, who was baptized in a church, return to Islam, and what are the conditions for that?

The girl mentioned, at this age, has not reached the age of accountability (تكليف), and there is no sin upon her for what her father did. She is considered Muslim by virtue of her father, as long as she is young, because a child follows the better of their two parents in religion. Thus, she is Muslim and not an apostate. Her father must be diligent in raising her according to the creed and ethics of Islam, and beware of returning to such an act.