I added it in my header.php file after <head> and <body> as instructed in GTM. Complete code of my header looks like this:
`<?php
/**
* The template for displaying the header.
*
* @package GeneratePress
*/
if ( ! defined( ‘ABSPATH’ ) ) {
exit; // Exit if accessed directly.
}
?><!DOCTYPE html>
<html <?php language_attributes(); ?>>
<head>
<!– 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-55M6XZ8′);</script>
<!– End Google Tag Manager –>
<meta charset=”<?php bloginfo( ‘charset’ ); ?>”>
<link rel=”profile” href=”https://gmpg.org/xfn/11″>
<?php wp_head(); ?>
</head>
<body <?php body_class(); ?>
<!– Google Tag Manager (noscript) –>
<noscript><iframe src=”https://www.googletagmanager.com/ns.html?id=GTM-55M6XZ8″
height=”0″ width=”0″ style=”display:none;visibility:hidden”></iframe></noscript>
<!– End Google Tag Manager (noscript) –>
<?php generate_do_microdata( ‘body’ ); ?>>
<?php
/**
* wp_body_open hook.
*
* @since 2.3
*/
do_action( ‘wp_body_open’ ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound — core WP hook.
/**
* generate_before_header hook.
*
* @since 0.1
*
* @hooked generate_do_skip_to_content_link – 2
* @hooked generate_top_bar – 5
* @hooked generate_add_navigation_before_header – 5
*/
do_action( ‘generate_before_header’ );
/**
* generate_header hook.
*
* @since 1.3.42
*
* @hooked generate_construct_header – 10
*/
do_action( ‘generate_header’ );
/**
* generate_after_header hook.
*
* @since 0.1
*
* @hooked generate_featured_page_header – 10
*/
do_action( ‘generate_after_header’ );
?>
<div id=”page” <?php generate_do_element_classes( ‘page’ ); ?>>
<?php
/**
* generate_inside_site_container hook.
*
* @since 2.4
*/
do_action( ‘generate_inside_site_container’ );
?>
<div id=”content” class=”site-content”>
<?php
/**
* generate_inside_container hook.
*
* @since 0.1
*/
do_action( ‘generate_inside_container’ );