functions.php

<?php

add_action ('wp_enqueue_scripts', 'load_custom_styles');
function load_custom_styles() {
    wp_enqueue_style(
    'custom',
    get_template_directory_uri() . '/css/custom.css'
    );

    wp_enqueue_script(
    'custom-script',
    get_template_directory_uri() . '/js/custom.js',
    array ( 'jquery' ),
    false,
    "all");
}