All posts and pages have the following fields to override the default page title and meta description, which is sometimes used by search engines.
Out of the box, WordPress is an excellent choice for SEO and is already well optimised. However, these fields can be an effective way of crafting specific descriptions for search engines to read.
Note that search engines have many different ways of ranking pages as well as determining the content of a page and what they choose to display in search results.
So these fields are just one factor in improving your search visibility.