Install GA4 and GTM on WordPress

Option 1: GTM4WP plugin (easiest)

1. Go to Plugins → Add Plugin and search for GTM4WP (Google Tag Manager for WordPress).
2. Install and activate it.
3. Open Settings → Google Tag Manager, paste your GTM- ID and save.

The plugin adds both GTM snippets to every page for you.

Option 2: Site Kit by Google

Site Kit is Google’s official plugin. Install it, connect your Google account, and turn on the Analytics and Tag Manager modules. It places the code for you and shows basic reports inside WordPress.

Option 3: Your theme’s header code field (no plugin)

Some themes have a setting for custom scripts in the page head. If yours does, paste the GTM head snippet below there and save.

<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->

The noscript part only matters for visitors with JavaScript turned off, so GTM works without it.

Option 4: Child theme code (developers)

Add both snippets with WordPress hooks in your child theme‘s functions.php, so a theme update never removes them.

// Child theme functions.php
add_action( 'wp_head', function () { ?>
<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->
<?php }, 1 );

add_action( 'wp_body_open', function () { ?>
<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->
<?php } );

On a plain HTML site you paste two snippets from GTM → Admin → Install Google Tag Manager into every page, or into the shared header and footer include if your site has one. Google’s install guide shows the same placement.

Step 1: Head snippet

Paste this as high in the <head> as possible.

<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->

Step 2: Body snippet

Paste this immediately after the opening <body> tag.

<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->

Where they go

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <!-- 1. GTM head snippet: as high in <head> as possible -->
  ...
</head>
<body>
  <!-- 2. GTM noscript snippet: right after the opening <body> tag -->
  ...
</body>
</html>

Replace GTM-XXXXXXX with your own Container ID.