Change Meeting Booking Topic Example

functions.php

<?php
add_filter('vczapi_woo_addon_create_meeting_params','umberto_change_booked_meeting_title',10,4);
function umberto_change_booked_meeting_title($meeting_params,$wc_booking, $product_id, $order_id){
    $meeting_params['meetingTopic'] = get_post_meta($order_id, 'wpcf-meeting-topic', true);
    return $meeting_params;
}