New field in email form

      $name = tep_db_prepare_input($HTTP_POST_VARS['name']);
      $email_address = tep_db_prepare_input($HTTP_POST_VARS['email']);
      $enquiry = tep_db_prepare_input($HTTP_POST_VARS['enquiry']);

Change to:

    $name = tep_db_prepare_input(ucwords($_POST['name']));
    $email_address = tep_db_prepare_input($_POST['email']);
    $phone = tep_db_prepare_input($_POST['phone']);
    $subject = tep_db_prepare_input(ucwords($_POST['subject']));
    $enquiry = tep_db_prepare_input(ucwords($_POST['enquiry']));

        $text = ENTRY_NAME . ' ' . $name
           . "n" . TEXT_CUSTOMMER_NR . ' ' . $customer_id
           . "n" . ENTRY_TELEPHONE_NUMBER . ' ' . $phone
           . "n" . ENTRY_EMAIL . ' ' . $email_address
           . "nn" . BOX_HEADING_SUBJECT . ' ' . $subject
           . "n" . ENTRY_ENQUIRY . "n" . $enquiry;

Find:

      if ($error == false) {
          tep_mail(STORE_OWNER, STORE_OWNER_EMAIL_ADDRESS, EMAIL_SUBJECT, $enquiry, $name, $email_address);

Change to:

      if ($error == false) {
          tep_mail(STORE_OWNER, STORE_OWNER_EMAIL_ADDRESS, EMAIL_SUBJECT, $text, $name, STORE_OWNER_EMAIL_ADDRESS, $phone);

Find:

      <tr>
        <td class="fieldKey"><?php echo ENTRY_NAME; ?></td>
        <td class="fieldValue"><?php echo tep_draw_input_field('name'); ?></td>
      </tr>
      <tr>
        <td class="fieldKey"><?php echo ENTRY_EMAIL; ?></td>
        <td class="fieldValue"><?php echo tep_draw_input_field('email'); ?></td>
      </tr>

Change to:

      <tr>
        <td class="fieldKey"><?php echo ENTRY_NAME; ?></td>
        <td class="fieldValue">
        <?php if (isset($_SESSION['customer_id'])) {
        echo (isset($account['name']) ? tep_draw_hidden_field('name',$name) : tep_draw_input_field('name', $name, 'size="45" maxlength="45" required aria-required="true" readonly="readonly" id="inputFromName" placeholder="' . ENTRY_NAME . '"'));
        }else{
        echo (isset($account['name']) ? tep_draw_hidden_field('name',$name) : tep_draw_input_field('name', $name, 'size="45" maxlength="45" required aria-required="true" id="inputFromName" placeholder="' . ENTRY_NAME . '"'));
        }?>
        </td>
      </tr>
      <tr>
        <td class="fieldKey"><?php echo ENTRY_EMAIL; ?></td>
        <td class="fieldValue"><?php echo (isset($account['email']) ? $email . tep_draw_hidden_field('email',$email) : tep_draw_input_field('email', $email, 'size="45" maxlength="45" required aria-required="true" id="inputFromEmail" placeholder="' . ENTRY_EMAIL . '"')); ?></td>
      </tr>
      <tr>
        <td class="fieldKey"><?php echo ENTRY_TELEPHONE_NUMBER; ?></td>
        <td class="fieldValue"><?php echo (isset($account['phone']) ? $phone . tep_draw_hidden_field('phone',$phone) : tep_draw_input_field('phone', $phone, 'size="45" maxlength="45" required aria-required="true" id="inputFromPhone" placeholder="' . ENTRY_TELEPHONE_NUMBER . '"')); ?></td>
      </tr>
      <tr>
        <td class="fieldKey"><?php echo BOX_HEADING_SUBJECT; ?></td>
        <td class="fieldValue"><?php echo tep_draw_input_field('subject', $subject, 'size="45" maxlength="45" required aria-required="true" id="inputFromSubject" placeholder="' . BOX_HEADING_SUBJECT . '"'); ?></td>
      </tr>

in catalog/includes/languages/english/contact_us.php
add:

define('BOX_HEADING_SUBJECT', 'Subject:');
define('ENTRY_TELEPHONE_NUMBER', 'Phonenumber:');