The document discusses Advanced Custom Fields (ACF), a plugin that allows adding custom fields to WordPress posts and pages beyond the default title and content fields. ACF offers both free and paid Pro versions, with the Pro version providing additional field types like repeaters and galleries. The document provides examples of how to create ACF field groups and templates to display ACF field values. It compares ACF to custom post types, noting ACF is useful for editing specific content blocks within a page template or when the content changes but layout stays the same.