how to draw a aiming line

I am making a ninja game and what i want to happen is when you hold the button down to throw a ninja star a line appears starting at the hand and ending where the star will land, and i would like it to show the arch that it would take (if i threw it straight up the line's arch would go up to the highest point, curve and go down to the end point.) This is kind of like assassin's creed with the hidden gun line aimer but i want it to curve.

Trail Arc Renderer - This is a script that will draw an arc.

Using the trail arc renderer, you can have an invisible projectile that uses the Trail Arc Renderer, then when the arc is complete, `Destroy()` the invisible projectile (but keep the arc renderer). Do this every frame

Also you will probably need to modify the Trail Arc Renderer a bit so that the trail stays.

Edit: To figure out if the mouse is being held down (C#)

void Update() {
   if (Input.GetButton("Fire1")) { 
      // mouse is being pressed