Use composer package manager
composer require saulmoralespa/billetera-personal-api-php// ... please, add composer autoloader first
include_once __DIR__ . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . 'autoload.php';
// import client class
use BilleteraPersonal\Client;
$user = getenv('USER');
$password = getenv('PASSWORD');
$billeteraPersonal = new Client($user, $password);