Code

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SphereController : MonoBehaviour {
private Rigidbody rb; 
void Start () {
rb=GetComponent<Rigidbody>();
}
void FixedUpdate () {
                       float moveHorizontal = Input.GetAxis("Horizontal");
                       float moveVertical = Input.GetAxis("Vertical");
                        Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);
                         rb.AddForce(movement);
}}