EnemyBullet.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class EnemyBullet : MonoBehaviour
{

    public float speed = -10f; //speed of the bullet
    public Rigidbody2D rb; //buller prefab
    public int damage = 1; //how much damage will be done

    void Start()
    {
        rb.velocity = transform.right * speed;
        //allows the bullet to go forward
    }

    void OnTriggerEnter2D(Collider2D hitInfo)
    {
        PlayerHealth player = hitInfo.GetComponent<PlayerHealth>(); //checks if object collided with has the script player health
        if (player != null)
        {
            player.TakeDamage(damage);
            Destroy(gameObject);//damages the player when collided with it
        }
       
        //destroys the object it hits

       
    }

}