There are two types of pages in the HeadwayThemes visual manager - Pages and System Pages.
Pages are equivalent to WordPress pages - they are custom content pages created in the WordPress admin area that appear in the navigation menu. Users can create and delete Pages.
System Pages are equivalent to WordPress posts - they are templates used by WordPress to display posts in different formats like by category, date, author, tag etc. Users cannot create or delete System Pages as they are theme-generated templates.
The key difference is that Pages are custom content while System Pages are templates used to display posts.