Movement(With jump feature).cs

using UnityEngine;

public class Movement : MonoBehaviour
{
    [SerializeField]
    private float movementSpeed;

    [SerializeField]
    private float jumpPower;

    private bool grounded;

    private float groundCheckDistance = 1;

    private float boxColliderHeight = .1f;

    private float sizeDivisor = 1.1f;

    private Vector3 size;

    private BoxCollider boxCollider;

    private new Rigidbody rigidbody;

    void Start()
    {
        boxCollider = GetComponent<BoxCollider>();
        rigidbody = GetComponent<Rigidbody>();
        size = new Vector3(boxCollider.size.x / sizeDivisor, boxColliderHeight, boxCollider.size.z / sizeDivisor);
    }

    void Update()
    {
        float h = Input.GetAxis("Horizontal");
        float v = Input.GetAxis("Vertical");
        Vector3 velocity = new Vector3(h, 0, v);
        velocity = transform.TransformDirection(velocity);
        velocity *= movementSpeed;
        velocity -= rigidbody.velocity;

        rigidbody.AddForce(velocity);

        var center = transform.TransformPoint(boxCollider.center);
        grounded = Physics.BoxCast(center, size, Vector3.down, transform.rotation, groundCheckDistance);

        if (Input.GetButtonDown("Jump") && grounded)
        {
            rigidbody.AddForce(Vector3.up * jumpPower);
        }
    }
}