Android Question Send push messages to App from HTML page

<?php
function push_notification_php($titulo, $cuerpo) {

    $url = 'https://fcm.googleapis.com/fcm/send';

    /* authorization_key */
    $authorization_key = 'place here yours';

    $fields = array(
          'to'=>'/topics/general',
          'priority'=>'high',
          'data'=>array(
                    'title'=>$titulo,
                    'body'=> $cuerpo
                    )
        );

    $fields = json_encode($fields);


    $headers = array (
            'Content-Type: application/json',
            'Authorization:key=' . $authorization_key
            );

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);

    $result = curl_exec($ch);
    
    curl_close($ch);

    if (strpos($result, 'message_id') !== FALSE) {
        return true;
        }
    else {
        return false;
        }

}

?>