how to use helpers in laravel code example

Example 1: how to share a helper globally laravel

'App\Providers\HelperServiceProvider',

Example 2: how to share a helper globally laravel

<?php
function getDomesticCities()
{
$result = \App\Package::where('type', '=', 'domestic')
    ->groupBy('from_city')
    ->get(['from_city']);

return $result;
}