Break the throwing motion down into its various parts. Start a four-seam grip, getting the hand under the ball, elbow position, front shoulder and front foot toward the intended target.
Have her start from one knee, with the glove-side knee up, and making her concentrate on using a four-seam grip; taking the ball out of the glove and down, out and up with the hand on top of it; keeping the elbow above the shoulder; and making sure that the hand goes from above the ball to behind it as it is released, this takes the lower body out of the equation and develop proper arm action.
That is the proper technique. good luck