If you mean ‘tabs’ as in the way WooCommerce presents the Product Description, Attributes, and Review on the product page then take a look at the template files for WooCommerce. You can find them at ../wp-content/plugins/woocommerce/templates.
There’s a good article on customizing the templates at http://wcdocs.woothemes.com/codex/template-structure/
You need to follow these guidelines to make sure that your changes are upgrade safe.