$form = new Varien_Data_Form(array(
        'id' => 'edit_form',
        'action' => $this->getUrl(
            'mu_productembroidery_admin/embroidery/edit',
            array(
                '_current' => true,
                'continue' => 0,
            )
        ),
        'method' => 'post',
        'enctype' => 'multipart/form-data'
    ));
    $form->setUseContainer(true);
    $this->setForm($form);

    $fieldset = $form->addFieldset(
        'general',
        array(
            'legend' => $this->__('Details')
        )
    );

$this->_addFieldsToFieldset($fieldset, array(
        'name' => array(
            'label' => $this->__('Name'),
            'input' => 'text',
            'required' => true,
        ),
        'file' => array(
            'label'     => $this->__('File path'),
            'required'  => false,
            'class'     => 'disable',
            'input'     => 'file',
            'name'      => 'file'
        ),
    ));