Hello. Is it possible to show my ad in posts of a specific category? Thank You
Yes, you can do this with AdPlugg's Section/Category targeting feature. Here's how to do it:
Note that as described in the on screen instructions, you will need to have your categories declared on the page either via Schema.org Article/articleSection schema or Open Graph article:section tags. If you are using WordPress, this can be easily done by installing the Yoast SEO plugin.