Hello,
When you edit the Product on the Site > the first thing that you see after adding the Product Title is the Description area > there you can change or edit the Product Description for a Product: https://snipboard.io/otPdvR.jpg
Further, if you want you can edit the Description of a Product with the page builder plugin (i.e. Elementor or WPBakery) active on your Site: https://snipboard.io/MAE4aO.jpg
Secondly, the Additional Information tab isn’t directly editable. It comes from WooCommerce by default and it is shown on those Products only which we have Attributes define on them > if a Product doesn’t have Attributes defined, the Additional Information tab doesn’t show: https://snipboard.io/DcBTbP.jpg
Best Regards
.
