Smooth movement when input is pressed

Well, I'm beginner in this and my question is how to move an object to it's right smoothly when player pressed right? I've tried this, but I've to keep pressing the button. I want only one push button and the object move until the destination.

     var smoothTime = 0.3;
     var isMoov = false;
     private var velocity = Vector3.zero;
     
     function Update () {
         if(Input.GetButton("Horizontal")){
             var in_direction : int = Input.GetAxis("Horizontal") < 0 ? -1 : 1;
             if(in_direction == 1){            
                 
                 var targetPosition : Vector3 = Vector3(25, 25, 25);                               
                 transform.position = Vector3.SmoothDamp(transform.position, targetPosition,
                                      velocity, smoothTime);
             }            
         }    
     }