Proses simpan ke database - https://solusipress.com/menyimpan-data-contact-form-7-pada-custom-table/

cf7-chained-select.php

<?php
function wpcf7_contacts_save_to_db( $cf, $result ) {
  $submission = WPCF7_Submission::get_instance();
    if ( ! $submission || ! $posted_data = $submission->get_posted_data() ) {
    return;
  }
  if( $result['status'] == 'mail_sent' ) {
    global $wpdb;

    if( !is_numeric( $posted_data['province'] ) ) $posted_data['province'] = null;
    if( !is_numeric( $posted_data['regency'] ) ) $posted_data['regency'] = null;
    if( !is_numeric( $posted_data['district'] ) ) $posted_data['district'] = null;
    if( !is_numeric( $posted_data['village'] ) ) $posted_data['village'] = null;

    $values = array(
      'full_name' => $posted_data['your-name'],
      'email' => $posted_data['your-email'],
      'address' => $posted_data['your-address'],
      'province_id' => $posted_data['province'],
      'regency_id' => $posted_data['regency'],
      'district_id' => $posted_data['district'],
      'village_id' => $posted_data['village'],
      'subject' => $posted_data['your-subject'],
      'message' => $posted_data['your-message'],

      'ip_address' => $_SERVER['REMOTE_ADDR'],
      'submit_date' => date("Y-m-d H:i:s"),
      'user_agent' => $_SERVER['HTTP_USER_AGENT']
    );

    $inserted = $wpdb->insert(
      $wpdb->prefix.'contacts',
      $values,
      array(
        '%s', '%s', '%s',
        '%s', '%s', '%s', '%s',
        '%s', '%s',
        '%s', '%s', '%s'
      )
    );
  }
}
add_action( 'wpcf7_submit', 'wpcf7_contacts_save_to_db', 20, 2 );