I'm unable to implement touch control in unity for my c# script, what's wrong with this code, not working

Look i'm total noob in unity scripting, could you please tell me what's wrong with this code, i'm not able to implement the touch, i want when user taps on the screen, to store that x and y coordinate and move the object to that location, i'm pasting the code, please tell me how to implement it

 void controlTouch()
 {
     float x,z;
     Vector3 mousePos = Input.mousePosition;
     mousePos = cam.ScreenToWorldPoint(new Vector3(mousePos.x, mousePos.y, cam.transform.position.y - transform.position.y));
     targetRotation = Quaternion.LookRotation(mousePos - new Vector3(transform.position.x, 0, transform.position.z));
     transform.eulerAngles = Vector3.up * Mathf.MoveTowardsAngle(transform.eulerAngles.y, targetRotation.eulerAngles.y, rotationSpeed * Time.deltaTime);
     if(Input.touches.Length > 0)
     {
         //if(Input.touches[0].phase == TouchPhase.Moved)
         //{
             x = Input.GetTouch(0).deltaPosition.x;
             z = Input.GetTouch(0).deltaPosition.y;
             //x = Input.touches[0].deltaPosition.x * runSpeed * Time.deltaTime;
             //z = Input.touches[0].deltaPosition.y * runSpeed * Time.deltaTime;
         //}
         /*else
         {
             x = 0.0f;
             z = 0.0f;
         }*/
     }
     else
     {
         x = 0.0f;
         z = 0.0f;
     }
 
     Vector3 input = new Vector3(x,0,z);
     currentVelocityModifer = Vector3.MoveTowards(currentVelocityModifer,input,acceleration * Time.deltaTime);
     Vector3 motion = currentVelocityModifer;
     motion *= (Mathf.Abs(input.x) == 1 && Mathf.Abs(input.z) == 1) ? 0.7f : 1;
     motion *= (Input.GetButton("Run")) ? runSpeed : walkSpeed;
     motion += Vector3.up * -8;
 
     controller.Move(motion * Time.deltaTime);
 
 }