Videl is the daughter of Hercule Satan and is one of the strongest humans on earth in Dragon Ball Z, the human members of the Z Fighters are probably the only humans who surpass her. Videl uses her fighting talent to stop criminals.
Videl meets Gohan at the high school they attend and keeps a close eye on him when he acts strangely. She eventually finds out that he is the one behind the mask of the Great Saiyaman and threatens to reveal his identity if he doesn't teach her how to fly like him. He agrees, not that he really had much of a choice, and manages to teach both her and his younger brother Goten how to fly.
Videl eventually falls in love with Gohan and they get married. By the very end of Dragon Ball Z their daughter Pan is introduced who becomes one of the main characters in Dragon Ball GT.