title: Code for add or update Invoice in code wise using PHP v3 SDK for QBO
body: <p>I am using "PHP v3 SDK for QBO". I edited customer_query.php in the _sample folder to get the customer &amp; which is working fine. Like this   how can I  add &amp; upadte the invoice against a customer in code wise. I did not find any example in the sample folder of PHP v3 SDK for QBO. Please help me how can i add or update an invoice (Using v3 SDK for QBO). Please give code for this.  </p>