how to make an enemies shoot and walk in unity code example

Example: how to make a shooting enemy ai in c#

//Put this on your bullet prefab, and rename Player to what your character's name is.
 float moveSpeed = 7f;

    Rigidbody2D rb;

    Player target;

    Vector2 moveDirection;

    void Start()
    {
        rb = GetComponent<Rigidbody2D>();
        target = GameObject.FindObjectOfType<Player>();
        moveDirection = (target.transform.position - transform.position).normalized * moveSpeed;
        rb.velocity = new Vector2(moveDirection.x, moveDirection.y);
        Destroy(gameObject, 3f);
    }

    void OnTriggerEnter2D(Collider2D col)
    {
        if (col.gameObject.name.Equals("Player"))
        {
            Debug.Log("Hit!");
            Destroy(gameObject);
        }
    }

//Put this on your enemy in a different script.
 [SerializeField]
    GameObject Bullet;

    float fireRate;
    float nextFire;

    void Start()
    {
        fireRate = 1f;
        nextFire = Time.time;
    }

    void Update()
    {
        CheckIfTimeToFire();
    }

    void CheckIfTimeToFire()
    {
        if(Time.time > nextFire)
        {
            Instantiate(Bullet, transform.position, Quaternion.identity);
            nextFire = Time.time + fireRate;
        }
    }

//Thats It!