$mail = new Zend_Mail('utf-8');
$mail->setType(Zend_Mime::MULTIPART_RELATED);
$mail->setBodyHtml($html);
$mail->setFrom('penawaran@mail.id', 'Nekindo');
$mail->addTo('mail@mail.com', 'Syahidah Humairoh');
$mail->setSubject('subject');
    try {
        $mail->send();
        Mage::getSingleton('core/session')->addSuccess('Your request has been sent');
        $this->_redirect('offer');
    }
    catch (Exception $e) {
        Mage::getSingleton('core/session')->addError('Unable to send.');
        $this->_redirect('offer');
    }

$pdfName="Penawaran";
$pdf->Output(Mage::getBaseDir().'/media/tmp/'.$pdfName.'.pdf', 'F');
$pdfurl=Mage::getBaseDir().'/media/tmp/'.$pdfName.'.pdf';
     $mail->createAttachment(
                    file_get_contents($pdfurl),
                    'application/pdf',
                    Zend_Mime::DISPOSITION_ATTACHMENT,
                    Zend_Mime::ENCODING_BASE64,
                    $pdfName.'.pdf'
                );

$mail->createAttachment(
            Zend_Pdf::load($pdfFilePath)->render(),
            'application/pdf',
            Zend_Mime::DISPOSITION_ATTACHMENT,
            Zend_Mime::ENCODING_BASE64,
                      'My_Custom_Filename.pdf'
        );