I am not sure where exactly would you like to put it and how it should look like?
Add some “VIP Ads” small banner on the featured Ads ?
To do that you would need to open file wpadverts/templates/list-item.php and add there somewhere a code like
<?php if( get_post( get_the_ID() )->menu_order > 0 ): ?>
<span class="vip-ads">VIP ADS</span>
<?php endif; ?>
and style it a bit to look like you would like it to look.
Note the changes you do in the original template files will be overwritten on WPAdverts update, to avoid that consider creating a child template file as explained here https://wpadverts.com/documentation/child-themes-and-templates/
