character not jumping

character cant jump but can move , i am working in 2D code : using System.Collections; using System.Collections.Generic; using UnityEngine;

public class muvz : MonoBehaviour { public float speed = 12f; public float jump = 5f;

 private Rigidbody2D rb;
 private Vector2 velocity;

 void Start ()
 {
     rb = gameObject.GetComponent<Rigidbody2D>();    
 }
 

 void Update ()
 {
     float xpos = Input.GetAxis("Horizontal") * speed * Time.deltaTime;
     transform.Translate(xpos, 0, 0);

     if (Input.GetButtonDown("Jump"))
     {
         rb.AddForce(Vector2.up * jump);
     }
 }

}

pls tell me whats wron with code