Hello, @TFS,
1. If you are using the “Product Layout Builder”, then you have to go to XStore >> Theme Settings >> WooCommerce >> Single Product Builder >> Tabs and change the “Type” from there, save changes and check back your site after removing the browser cache.
2. If you are using the “default/prebuilt” layout for the single product page, then you have to go to XStore >> Theme Settings >> WooCommerce >> Single Product Page >> Tabs and Choose the “Tabs Type” as “Default”, Publish the changes and check back to your site after removing the browser cache.
Regards 8Themes Team.