wp_enqueue_style('custom-style', get_stylesheet_directory_uri() . '/custom.css');
function my_child_theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'child-style', get_stylesheet_directory_uri() . '/style.css', array('parent-style') );
}
add_action( 'wp_enqueue_scripts', 'my_child_theme_enqueue_styles' );
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://godigital.novumlabs.net/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://godigital.novumlabs.net/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://godigital.novumlabs.net/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://godigital.novumlabs.net/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://godigital.novumlabs.net/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>