WordPress

The simplest path on WordPress is the free WPCode plugin (formerly Insert Headers and Footers) — 3M+ active installs and a one-field header snippet box.

Steps (WPCode plugin)

1. In WP Admin, go to Plugins → Add New and search for WPCode.

2. Install and activate WPCode — Insert Headers and Footers + Custom Code Snippets.

3. Code Snippets → Header & Footer.

4. In the Header box, paste:

   <script id="visitorleadjs" async src="https://ingest.visitorlead.tech/vl.js" data-code="YOUR_SITE_CODE"></script>

5. Save Changes at the bottom of the page.

Alternative — child theme header.php

If you don't want a plugin and use a child theme, add this to your child theme's functions.php:

add_action('wp_head', function () {
  echo '<script id="visitorleadjs" async src="https://ingest.visitorlead.tech/vl.js" data-code="YOUR_SITE_CODE"></script>';
});

Don't edit the parent theme directly — your changes will be lost on theme updates.

Official references

• WordPress: wp_head hook reference — developer.wordpress.org
• WPCode plugin — wordpress.org plugin directory