A simple WordPress plugin that has a cron schedule. Visit https://www.davidangulo.xyz/ for more information.

cron.php

<?php
/*
Plugin Name: My cron WordPress plugin
Plugin URI: wordpress.org/plugins
Description: A simple WordPress plugin that executes many times in a certain interval.
Version: 1.0.0
Author: David Angulo
Author URI: https://www.davidangulo.xyz/
License: GPL2
*/

register_activation_hook( __FILE__,"register_schedule");
function register_schedule() {
  if(!wp_next_scheduled("my_daily_event")) {
		wp_schedule_event(strtotime("06:00:00"),"daily","my_daily_event");
	}
}

add_action("my_daily_event","do_this_daily");
function do_this_daily() {
  	wp_mail("some.email@example.xyz","Morning Message","Good Morning! Have a nice day. :)");
}

register_deactivation_hook( __FILE__,"remove_schedule");
function remove_schedule() {
	wp_clear_scheduled_hook("my_daily_event");
}

add_filter("cron_schedules","custom_cron_schedules");
function custom_cron_schedules($schedules){
    if(!isset($schedules["5minutes"])){
        $schedules["5minutes"] = array(
            'interval' => 5*60,
            'display' => __('Once every 5 minutes'));
    }
    if(!isset($schedules["halfhour"])){
        $schedules["halfhour"] = array(
            'interval' => 30*60,
            'display' => __('Once every 30 minutes'));
    }
    return $schedules;
}

//Visit the tutorial for more information
//https://www.davidangulo.xyz/website-development/how-to-create-cron-job-in-wordpress/