Add the snippet once to the WordPress head. It then loads on every public page, including pages built with Elementor or other builders.
1. Copy the snippet
In Stellar, open the project for this site and copy the snippet from your domain settings. Leave Anti-Flicker on if you are running visual tests. Direct head install is what makes that work. How anti-flicker works.
2. Paste it on WordPress
Easiest path: install WPCode (Insert Headers and Footers). Add a site-wide header snippet and paste the Stellar code there.
Or paste it in your theme’s header.php, inside <head>, as high as you can. Use a child theme so a theme update does not remove it.
Save. Do not paste it in both the plugin and header.php.
Clear any cache plugin and your CDN.
WP Rocket, NitroPack, Autoptimize, and similar plugins will break the snippet if they minify, combine, or defer it. Exclude stellar.js and d3niuqph2rteir.cloudfront.net from JavaScript optimization, then clear cache.
3. Confirm it loaded
Open a published page in a private browser window. Editor and draft previews often hide the snippet.
Open developer tools and go to the Network tab.
Reload and look for stellar.js. If that request is there, the install is done.
If it does not load
Check a public page, not wp-admin.
If the script is missing or experiments flicker, the optimization plugin is the first place to look.
A page builder HTML widget is the wrong place. It only covers that page and loads too late.