PHP

wp enqueue

/** 
 *   Enqueue your theme styles and scripts in functions.php
 *   use time() instead of a proper versioning to avoid caching when developing
 */
function my_theme_enqueue_scripts() {
    wp_enqueue_style( 'default-style', get_stylesheet_uri(), [], '1.0.0', 'all' ); //default styles.css
    wp_enqueue_style( 'main-style', get_stylesheet_directory_uri() . '/assets/css/main.min.css', [], time(), 'all' );
    wp_enqueue_script( 'main-script', get_stylesheet_directory_uri() . '/assets/js/main.min.js', [], time(), false );
}
add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_scripts' );

enqueue wordpress

function wpdocs_theme_name_scripts() {
    wp_enqueue_style( 'style-name', get_stylesheet_uri() ); /* enqueues style.css */
    /* if you want to enqueue other styles use: */
    /* wp_enqueue_style( 'style-name', get_template_directory_uri() . '/css/your-style-name.css' ); */
    wp_enqueue_script( 'script-name', get_template_directory_uri() . '/js/example.js', array(), '1.0.0', true );
}
add_action( 'wp_enqueue_scripts', 'wpdocs_theme_name_scripts' );

enqueue wordpress

function my_scripts_method() {
    wp_enqueue_script(
        'custom-script',
        get_stylesheet_directory_uri() . '/js/custom_script.js',
        array( 'jquery' )
    );
}

add_action( 'wp_enqueue_scripts', 'my_scripts_method' );