HTML2PDF How to pass id to the html site to be converted

I´ve started using HTML2PDF (https://www.html2pdf.fr/) to create invoices, now the following code works:

try {
                ob_end_clean();
                ob_start();
                include('../faktura/fa.php');
                $html = ob_get_contents();
                ob_end_clean();
                $content = $html;
                $html2pdf = new Html2Pdf('P', 'A4', 'cs',true,"UTF-8");
                $html2pdf->setDefaultFont('freeserif');
                $html2pdf->pdf->SetFont('freeserif');
                $html2pdf->writeHTML($content);
                $pdfContent = $html2pdf->output('my_doc.pdf', 'S');
                } catch (Html2PdfException $e) {
                $html2pdf->clean();
                $formatter = new ExceptionFormatter($e);
                echo $formatter->getHtmlMessage();
            }

The content of fa.php is converted to pdf, however if I change one of the lines to:

include('../faktura/fa.php?id=105');

note that I only added ?id=105, it returns only a blank page. The php file fa.php includes:

 $id = (int) $_GET['id'];

What I need to do is to pass an ID to that php script so the invoice of the exact order is generated.