The Search & Filter Pro Text Search field uses the standard WordPress search, so looks only in the Post Title AND Content. To help you control this better, on the form’s Advanced settings tab you will see 2 settings for Relevanssi.

The documentation for this is here:

https://www.designsandcode.com/documentation/search-filter-pro/3rd-party/relevanssi/

You would need to install and activate the free Relevanssi plugin as well.

Then set Relevanssi up (to look also at Tags) and build its index (make sure it is indexing the desired post types AND the categories/tags/taxonomies/custom fields that you want to search). You can also select to search ONLY the titles, OR the content, and no taxonomies or custom fields.