Replace touch movement!

Hi, I'm starting slowly with Unity and I do not know much about programming. I need to change this, for tactile movement, which consists of a simple cube move from side to side, touching either side of the screen

 public GameObject cube;
 public float speed; 
 public float anglerotation;

 void FixedUpdate()
 {
     //zero rotation
     float turnAxisZ = 0;
     
     // left and right keys affect cube
     transform.Translate(Vector3.right * 
                         Input.GetAxis("Horizontal")*
                         speed *
                         Time.deltaTime
                         );
     
     // Calculating the left and right turn multiplying the rotation angle
     giroEnEjeZ = Input.GetAxis("Horizontal")* -anguloDeGiro;
     Cube.transform.rotation = Quaternion.Euler(0,0,giroEnEjeZ);
     
     }

@khokhani1510