It is a very easy thing to do with all our other templates, because there is a plugin called "Flexible VM2 Template" to do this.
But with FashionMart, there is no plugin to control those small customization. you need a hard coding.
To add SKU, the PHP line to print the SKU number is this:
For Category browse page:
<div class="ProductKU"><?php echo JTEXT::_('COM_VIRTUEMART_CART_SKU');?>: <?php echo $product->product_sku ?></div>
For product details page:
<div class="ProductKU"><?php echo JTEXT::_('COM_VIRTUEMART_CART_SKU');?>: <?php echo $this->product->product_sku ?></div>
The product details and category browse page PHP files are located here:
Category browse page:
ROOT/templates/<yourjoomlatemplate>/html/com_virtuemart/category/default.php
(default.php, flexv2.php; what ever you are currently using, there are multiple category browse page layouts and you are using only one of them depends on what ever you chose from VM Configuration)
Product Details page:
ROOT/templates/<yourjoomlatemplate>/html/com_virtuemart/productdetails/default.php
(default.php or flexv2.php. There are 2 different product details page layouts and you are using only one of them depends on what ever you chose from VM Configuration)
Then you can stylize this SKU text with using the CSS and the
.ProductKU class name. Something like;
.ProductKU {
text-size:10px;
}