generatePdfSendMail.php

<?php
...
// custom/modules/AOS_PDF_Templates/generatePdfSendMail.php

if ($task == 'pdf' || $task == 'emailpdf') {
    $file_name = $mod_strings['LBL_PDF_NAME'] . "_" . str_replace(" ", "_", $bean->name) . ".pdf";

    ob_clean();
    try {
        $orientation = ($template->orientation == "Landscape") ? "-L" : "";
        $pdf = new mPDF('en', $template->page_size . $orientation, '', 'DejaVuSansCondensed', $template->margin_left, $template->margin_right, $template->margin_top, $template->margin_bottom, $template->margin_header, $template->margin_footer);
        $pdf->SetAutoFont();
        $pdf->SetHTMLHeader($header);
        $pdf->SetHTMLFooter($footer);
        $pdf->WriteHTML($printable);
        if ($task == 'pdf') {
            $pdf->Output($file_name, "D");
        } else {
            $pdfPath = $sugar_config['upload_dir'] . 'attachfile.pdf';
            $fp = fopen($pdfPath, 'wb');
            fclose($fp);
            $pdf->Output($pdfPath, 'F');
            $account = BeanFactory::getBean('Accounts', $bean->billing_account_id);
            $primary_email = $account->emailAddress->getPrimaryAddress($account);
          
            $mailSubject = "Invoice for ".$bean->name;
            $mailBody = "<p>Hello customer, see attachment for your invoice</p>";
            /**
            * Here are calling the function defined earlier our custom/include/custom_utils.php
            * Passing all the required paramenters.
            */
            sendEmail($primary_email, $mailSubject, $mailBody, [
                'name' => $file_name,
                'path' => $pdfPath,
            ]);

        }
    } catch (mPDF_exception $e) {
        echo $e;
    }
} else{
    $log->fatal("Error occurred sending mail");
}

...