SerializeExample.cs

using UnityEngine;

public class SomePerson : MonoBehaviour
{
    //This field gets serialized because it is public.
    public string firstName = "John";

    //This field does not get serialized because it is private.
    private int age = 40;

    //This field gets serialized even though it is private
    //because it has the SerializeField attribute applied.
    [SerializeField]
    private bool hasHealthPotion = true;
}