How to theme PDF generated by Print module? I would like to theme the PDF generated by the Print module. I would like to add header, footer, margins, border to the generated PDF. 

The certificate module in Drupal provides theming to the certificate, but my site is almost like a read and get certified site, so I wish not to change print module.

I tried the form alter and other stuffs, but not sure from where the PDF can be changed.
You should on your creation of node call a function which will generate a pdf.
Use tcpdf class for it generate pdf and download  tcpdf functions./
Check also the link

 class my_pdf extends TCPDF { //Page header public function Header() { } // Page footer public function Footer() { } } 

$pdf = new my_pdf(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, UTF-8', false);

$pdf-&gt;setPrintHeader(true);
 $pdf-&gt;setPrintFooter(true); 
$pdf-&gt;SetMargins(25.0, 40, 25.0);
$pdf-&gt;SetFooterMargin(1.5);
$pdf-&gt;SetAutoPageBreak(TRUE, 50);
$pdf-&gt;setImageScale(PDF_IMAGE_SCALE_RATIO);
$pdf-&gt;AddPage();
$pdf-&gt;writeHTML($html, true, false, true, false, ''); 
$pdf-&gt;lastPage();
$pdf-&gt;Output('my_document.pdf', 'D');