Which pony is the daughter of Princess Cadance and Shining Armor?

The daughter of Princess Cadance and Shining Armor is Flurry Heart.

Flurry Heart is introduced in “The Crystalling,” the two-part season-six premiere of My Little Pony: Friendship Is Magic. She is an alicorn foal, meaning she has both a horn and wings, and her birth makes her a notable new member of Equestria’s royal family.

Her parents are Princess Cadance, ruler of the Crystal Empire, and Shining Armor, Twilight Sparkle’s older brother. Flurry Heart’s arrival is celebrated throughout the Crystal Empire, but her unusually powerful magic causes trouble when her emotions trigger uncontrolled spells and shatter the empire’s Crystal Heart.

She is sometimes confused with Twilight Velvet, who is Shining Armor’s mother and Twilight Sparkle’s mother. Crystal Prep is also associated with Cadance and Shining Armor in the human-world setting, but it is a school rather than their daughter.