By default, WooCommerce uses tabs to display the product description and additional information. But I have visited your site and checked the single product page. I think you are using a custom layout of the theme. Go to Layouts > Edit single product layouts and add the products tabs widgets in the layout.
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This is the product data tabs. The WooCommerce Additional Information tab in Product Pages is used to display product additional in WooCommerce. When you add information like weight, dimension, and other shipping details, they are automatically shown in the WooCommerce additional information tab on the product page.