Hi!
The results page layout cannot be affected by the plugin itself. It can only replace the results with it’s own, but it cannot print a custom text there, it is not possible. I believe you will have to edit the search.php theme file to do that, or contact the theme author for the exact location.
If you want taxonomy terms as well in the search results, you can choose the taxonomies to search for under the General Options -> Sources 2 panel: https://i.imgur.com/ZRblGpS.png
Relevan documentations
– Taxonomy terms as results