I did also have issue withthe pfd and I found this post:
Basically you add 4 lines to openemr/interface/patient_file/report/custom_report.php
right after $config_mpdf = Config_Mpdf::getConfigMpdf();
so you will get :
if ($PDF_OUTPUT) {
$config_mpdf = Config_Mpdf::getConfigMpdf();
$config_mpdf['margin_top'] = $config_mpdf['margin_top'] * 1.5; >
$config_mpdf['margin_bottom'] = $config_mpdf['margin_bottom'] * 1.5; >
$config_mpdf['margin_header'] = $GLOBALS['pdf_top_margin']; >
$config_mpdf['margin_footer'] = $GLOBALS['pdf_bottom_margin'];
$pdf = new mPDF($config_mpdf);
if ($_SESSION['language_direction'] == 'rtl') {
$pdf->SetDirectionality('rtl');
}