tabithatomsin

Thank you so much! This did it!

add_action( 'init', 'my_setcookie_example' );
    function my_setcookie_example() {
  $current_user = wp_get_current_user();
   setcookie( 'id', $current_user->ID, 3 * DAYS_IN_SECONDS, COOKIEPATH, COOKIE_DOMAIN );
    }