wordpress header code plugin

Question

Can anyone tell me how can i add a code to head.php of the theme via a plugin?

I want to add some external .css file in it?

Answer 1

You should use following code in your plugin:

add_action('wp_head', 'your_function');
   function your_function(){
      wp_register_style( 'external_css', 'EXTERNAL CSS PATH');           
      wp_enqueue_style('external_css');

   } 

FYI: May be you mention incomplete file name, it's should be header.php, please make sure. Hope this code helps you. All the best ;)