In padel, a sliced forehand volley is a shot in which you hit the ball with a slice, spinning it backward, while volleying near the net. This is how to do it:
Place your feet shoulder-width apart and stand near the net.
Make a quick swing forward while keeping your racket just above the ball height.
To add a small slice and cause the ball to spin backward as it flies, strike it with an open racket face.
Maintain a balanced position with your feet while making a brief follow-through with your racket.
Slowing down the ball and making it harder for your opponent to predict its trajectory and return it successfully are the objectives of the sliced forehand volley.
A good video about it here.