How to add custom shortcode for plugin woocommerce whatsapp notification

wwn_add_custom_shortcode.php

<?php

/**
 * Register shortcodes
 * 
 * You should register your custom shortcode using filter wwn_shortcodes, that filter has params array and must be return as array
 * 
 * @param array $shortcodes
 * @return array
 */
add_filter('wwn_shortcodes', 'wwn_register_new_shortcodes');
function wwn_register_new_shortcodes($shortcodes) {
    return array_merge($shortcodes, array(
        '{custom_shortcode}' => 'This is a description for the custom shortcode',
    ))
}

/**
 * Parse Shortcode
 * 
 * You should add filter to parse your custom shortcode. filter using patern like this: wwn_shortcode_parse_{your_custom_shortcode_without_brackets}.
 * 
 * @param string $value
 * @param int $order_id
 * @param WC_Order $order
 */
add_filter('wwn_shortcode_parse_custom_shortcode', 'wwn_parse_custom_shortcode', 15, 3);
function wwn_parse_custom_shortcode($value, $order_id, $order) {

    $value = 'The shortcode will be replace by this text. Very simple right.';

    return $value;
}