Hi,
You will need to go to Plugins\SevenSpikes.Nop.Plugins.NopQuickTabs\Views\ProductTab, open the _ProductTabsWithAjax.cshtml or _ProductTabsWithoutAjax.cshtml, depending if you are using the tabs with or without ajax, there you will find a foreach loop with the following content:
<li>
<a href="#[email protected]">@tabInfo.Title</a>
</li>
Place the h2 tag around the anchor tag.
Hope this helps!