Get path to the root folder to add stylesheet or script

get_stylesheet_directory_uri()

Here is the reference link: https://developer.wordpress.org/reference/functions/get_stylesheet_directory_uri/

A sample code:

function disa_scripts() {
	wp_enqueue_style( 'indexaf6c', get_stylesheet_directory_uri() . '/assfolder/assets/css/indexaf6c.css' );

	wp_enqueue_script( 'disa-navigation', get_template_directory_uri() . '/js/navigation.js', array(), _S_VERSION, true );
	wp_enqueue_script( 'rocket-loader', get_template_directory_uri() . '/assfolder/assets/js/rocket-loader.min.js', array(), _S_VERSION, true );
	}
add_action( 'wp_enqueue_scripts', 'disa_scripts' );

You need to put this code in your function.php file