[Support request] Hook in the Content Area

Hello there,

Try adding this snippet:

add_shortcode('portable_hook', function($atts){
	ob_start();
        $atts = shortcode_atts( array(
            'hook_name' => 'no foo'
        ), $atts, 'portable_hook' );
		do_action($atts['hook_name']);
	return ob_get_clean();
});

add_filter( 'the_content', 'insert_custom_hook', 20 );
function insert_custom_hook( $content ) {
    global $post;
    $inserted_hook = do_shortcode('[portable_hook hook_name="after_post_content"]');
    if ( is_single() && ! is_admin() ) {
        return $content . $inserted_hook;
    }
    return $content;
}

Adding PHP: https://docs.generatepress.com/article/adding-php/#code-snippets

After activating this PHP snippet on your site, you can hook things at the end of the content using after_post_content hook.

That hook is added directly after the Content.

You can use the same Hook to add your advertisement.