WordPress Enqueue Scripts & Styles

      // Enqueue external script
function child_theme_scripts() {
    wp_enqueue_script(
        'external-js',
        'https://example.com/external.js',
        array(),
        '1.0',
        true
    );
}
add_action('wp_enqueue_scripts', 'child_theme_scripts');

// Enqueue external stylesheet
function enqueue_external_styles() {
    wp_enqueue_style(
        'external-css',
        'https://example.com/styles.css',
        array(),
        '1.0'
    );
}
add_action('wp_enqueue_scripts', 'enqueue_external_styles');

// Localize script for AJAX
function my_ajax_setup() {
    wp_localize_script('my-script', 'myAjax', array(
        'ajaxurl' => admin_url('admin-ajax.php'),
        'nonce'   => wp_create_nonce('my_nonce'),
    ));
}
add_action('wp_enqueue_scripts', 'my_ajax_setup');