The Settings & Defaults box contains various options to do with the specific Search Form you are editing, such as which post types to search in, various front end behaviours and adding restrictions such as searching within specific categories only.

Tabs

1. General – the most frequently used and general options for your search form
2. Display Results – All the options relating the to the output of your results & Ajax
3. Posts – Choose various options relating to posts – such as the default sort order, the post status to search in and any post IDs to exclude
4. Tags, Categories & Taxonomies – include / exclude tags, categories and taxonomies from your search results
5. Post Meta – Add post meta conditions to apply to all searches, such as searching only `instock` items
6. Advanced – this contains some less used settings – and will also contain any 3rd Party plugin specific settings