Tags are keywords or labels that help organize the products and simplify the search on the site. For example, for a Nokia cell phone, they can be: nokia, phone, wi-fi, mp3, 3G,GPS. The tags will be displayed in the product page and if you click on one of the tags, then the page will display all the products that contain the same tag.
In order to add tags, go to Product Catalog - Product List and on the edit / add product page, in the "Product keywords (tags)" field, enter the keywords and click on the add icon.
The product tags will appear in the product page or in the left menu if the "Tags" module from the Content - Modules settings menu is active.
Listed in: Catalog settings