If you don’t want to show to the customer the empty attributes of your products in the PDP, for example in the More Information tab, such like this:

You will need to do the following:

• Override the file vendor/magento/module-catalog/view/frontend/templates/product/view/attributes.phtml into your theme:

or

• Edit your theme new file, adding the following code:
  
  1	<?php if($_data['value'] == 'N/A') continue;?>

  
  just below this:
  
  1	<?php foreach ($_additional as $_data): ?>

• So, this should be the full code of your phtml:
  
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

  <?php /** * Copyright © Magento, Inc. All rights reserved. * See COPYING.txt for license details. */   // @codingStandardsIgnoreFile   /** * Product additional attributes template * * @var $block \Magento\Catalog\Block\Product\View\Attributes */ ?> <?php     $_helper = $this->helper('Magento\Catalog\Helper\Output');     $_product = $block->getProduct(); ?> <?php if ($_additional = $block->getAdditionalData()): ?>     <div class="additional-attributes-wrapper table-wrapper">         <table class="data table additional-attributes" id="product-attribute-specs-table">             <caption class="table-caption"><?= /* @escapeNotVerified */ __('More Information') ?></caption>             <tbody>             <?php foreach ($_additional as $_data): ?> <?php if($_data['value'] == 'N/A') continue;?>                 <tr>                     <th class="col label" scope="row"><?= $block->escapeHtml(__($_data['label'])) ?></th>                     <td class="col data" data-th="<?= $block->escapeHtml(__($_data['label'])) ?>"><?= /* @escapeNotVerified */ $_helper->productAttribute($_product, $_data['value'], $_data['code']) ?></td>                 </tr>             <?php endforeach; ?>             </tbody>         </table>     </div> <?php endif;?>

• Clean the following folders:
  
  1 2 3

  rm var/cache rm view_preprocessed rm pub/static/frontend

  
  Or just clean cache and make an static content deploy instead.
• Try again, and you should get the following result: