Search within the relevant post or a specific category ?

I hope you are well today and thank you for your question.

Yes, you can configure the plugin search form to search specific post types, categories, or custom fields as described on the below pages.

https://ivorysearch.com/docs/search-specific-post-types/
https://ivorysearch.com/docs/search-specific-category-or-taxonomy-posts/
https://ivorysearch.com/docs/search-custom-fields-and-meta-boxes/

Best regards,

Thanks for your answer. The visitor must make this choice, not me! Whichever category he chooses, he should be able to search in that category. Is it possible?

Currently, the plugin does not provide this frontend filter search functionality but I will consider adding this in the future version of the plugin.