How to add styles to a WordPress plugin?

Question

PHP

How to properly include the css file in the plugin? I just can't handle it.

Answer 1

Only for the admin panel or for the site as a whole?
Generally speaking, then:

function themeslug_enqueue_style() {
  wp_enqueue_style( 'myStyle', plugins_url( '/css/myStyle.css', __FILE__ ), false ); 
}

add_action( 'wp_enqueue_scripts', 'themeslug_enqueue_style' );

Answer 2

you can write in style.css of the template itself