Using the plugin

They are not shortcodes. They are PHP code that you place in the functions.php of your theme or you can use them within your custom plugins.

Checkout:
https://codex.www.ads-software.com/Function_Reference/wp_enqueue_style

Here’s a usage example:

/**
 * Proper way to enqueue scripts and styles
 */
function theme_name_scripts() {
    wp_enqueue_style("jquery-ui");
    wp_enqueue_style("jquery-ui-accordion");
}

add_action( 'wp_enqueue_scripts', 'theme_name_scripts' );