Post, Page, Product and other Post Type Search
Search in all kinds of custom post types - including Posts, Pages, Products etc..
Search Sources -> Post Type Search -> Search in custom post types
By default the plugin is configured to return Posts and Pages as results. Use the Search in custom post types drag and drop option to change that.
Custom post types (or CPT as shorthand) are WooCommerce Products, Portfolio Items, Books, Tutorials etc..
When using the Regular Engine, then choosing the post types here is sufficient, no other configuration is required.
When using the Index Table engine, then make sure the selected post types on the search instance settings are also selected and indexed on the Index Table settings.
For each search instance you can choose different post types to search for - but make sure all of these are also indexed on the index table settings.