How to send email when my plugin is activated?

I offer you an idea that I have already used something like this.
I wanted to know the sites that my plugin uses, I created a cron job allow me to send me an email every week :

add_action('init', function() {
 $time = wp_next_scheduled('dro_cron_hook');
 wp_unschedule_event($time, 'dro_cron_hook');

 if (!wp_next_scheduled('dro_cron_hook')) {
    wp_schedule_event(time(), 'everyweek', 'dro_cron_hook');

add_filter('cron_schedules', function($schedules) {
$schedules['everyweek'] = array(
    'interval' => 604800
 return $schedules;

add_action('dro_cron_hook', function() {

 // Here you can send the email using wp_mail() and some additional data