A female's belly button (also known as the navel or umbilicus) is located on the abdomen, marking the site where the umbilical cord was attached during fetal development. It's the same location as a male's belly button.
Essentially, the belly button is a scar. After birth, the umbilical cord is clamped and cut. The remaining stump eventually dries up and falls off, leaving behind the navel. The appearance of the belly button (innie or outie) is determined by how the skin heals at this site, not by how the umbilical cord was cut.
Therefore, there's no difference in location of the belly button between males and females. It is always on the abdomen.