Show the final custom design in the order confirmation page

The order confirmation page is the final page once the customer finished the order. To make your customer able to see final custom design in this page, you need to add a custom javascript code on the checkout setting page.

• On your Shop Admin, go to 'Settings > Checkout'  page,
• Scroll down the page. You will find “Additional content & scripts” area.
• Put following code, and then click save button to save the changes.  

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script type='text/javascript' > 
$(document).ready(function() { 
 cst_idx = "{{ shop.metafields.customify.idx }}";
 $(".product__description__property").each(function() {
 theContent = $(this).html();
 parent = $(this).parents('tr');
 if ( theContent.indexOf(cst_idx) > -1 )
   {
      theContent = theContent.split(': ')[1];
      source = 'https://' + Shopify.Checkout.apiHost + '/apps/customify?show_custom=1&id=' + theContent; 
      parent.find('.product__image').find('img').attr('src',source)
   } 
 }); 
}); 
</script>