How to Add player Mobile control to move to my game?

I Can't find how to put mobile control to my game i tried some but they are not working. the thing that i want is when you drag the player will move here is my code:

  using UnityEngine;
  using System.Collections;
  
  [System.Serializable]
  public class Boundary 
  {
      public float xMin, xMax, yMin, yMax; //Screen Boundary dimentions
  }
  
  public class Player_Script : MonoBehaviour 
  {//1
      //Public Var
      public float speed;             //Player Ship Speed
      public Boundary boundary;         //make an Object from Class Boundary
      public GameObject shot;            //Fire Prefab
      public Transform shotSpawn;        //Where the Fire Spawn
      public float fireRate = 0.5F;    //Fire Rate between Shots
      public GameObject Explosion;    //Explosion Prefab
      
  
      //Private Var
      private float nextFire = 0.0F;    //First fire & Next fire Time
  
  
      // Update is called once per frame
      void Update () 
      {
      
              //Excute When the Current Time is bigger than the nextFire time
          if (Time.time > nextFire) 
          {
              nextFire = Time.time + fireRate;                                 //Increment nextFire time with the current system time + fireRate
              Instantiate (shot , shotSpawn.position ,shotSpawn.rotation);     //Instantiate fire shot 
              GetComponent<AudioSource>().Play ();                                                     //Play Fire sound
          }
          
          if (Input.touchCount > 0) 
         {
           // The screen has been touched so store the touch
           Touch touch = Input.GetTouch(0);
           
           if (touch.phase == TouchPhase.Stationary || touch.phase == TouchPhase.Moved) {
               // If the finger is on the screen, move the object smoothly to the touch position
               Vector3 touchPosition = Camera.main.ScreenToWorldPoint(new Vector3(touch.position.x, touch.position.y, 10));                
               transform.position = Vector3.Lerp(transform.position, touchPosition, Time.deltaTime);
           }
       }
          
      }    
          
  
      // FixedUpdate is called one per specific time
      void FixedUpdate ()
      {//3
      
          float moveHorizontal = Input.GetAxis ("Horizontal");                 //Get if Any Horizontal Keys pressed
          float moveVertical = Input.GetAxis ("Vertical");                    //Get if Any Vertical Keys pressed
          Vector2 movement = new Vector2 (moveHorizontal, moveVertical);         //Put them in a Vector2 Variable (x,y)
          GetComponent<Rigidbody2D>().velocity = movement * speed;                             //Add Velocity to the player ship rigidbody
  
          //Lock the position in the screen by putting a boundaries
          GetComponent<Rigidbody2D>().position = new Vector2 
              (
                  Mathf.Clamp (GetComponent<Rigidbody2D>().position.x, boundary.xMin, boundary.xMax),  //X
                  Mathf.Clamp (GetComponent<Rigidbody2D>().position.y, boundary.yMin, boundary.yMax)     //Y
              );
      }//3
  
      //Called when the Trigger entered
      void OnTriggerEnter2D(Collider2D other)
      {//2
          //Excute if the object tag was equal to one of these
          if(other.tag == "Enemy" || other.tag == "Asteroid" || other.tag == "EnemyShot") 
          {
              Instantiate (Explosion, transform.position , transform.rotation);                 //Instantiate Explosion
              SharedValues_Script.gameover = true;                                             //Trigger That its a GameOver
              Destroy(gameObject);                                                             //Destroy Player Ship Object
          }
      }//2
   }//1