Display the method of payment of an order on the invoice pdf comerce billy
You can use code below to get the payment method of an order by passing order id to the function. The order id on Commerce billy template file can be easily found in this variable $content['commerce_customer_billing']['#object']->order_id and some other variables as well:

$order_id = $content['commerce_customer_billing']['#object']-&gt;order_id;

$payment_method = '';
$order = commerce_order_load($order_id);
$r = explode('|', $order-&gt;data['payment_method']);

if (count($r) &gt; 1){
  $rule = rules_config_load($r[1]);
  $payment_method = $rule-&gt;label;
}


After using this function, you can print the payment method on your bill by printing $payment_method variable.