My script for movinfg character in 2D dosen't work.

Hi, I am new to proggraming and I make script for moving my 2d character. I run it but it dosen’t work and i don’t know what is wrong with it. Can someone help me?

Code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class movment : MonoBehaviour {

public float sp;
private Rigidbody2D rb;
private Vector2 mv;

void Start()
{
    GetComponent<Rigidbody2D>();
}
void Update()
{
    Vector2 moveInput = new Vector2(Input.GetAxis("Horizontal"), Input.GetAxis("Vertical"));
    mv = moveInput.normalized * sp;
}
void FixedUpdate()
{
    rb.MovePosition(rb.position + mv * Time.fixedDeltaTime);

}

}

void Start()
{
rb = GetComponent();
}

try That