The Default Template

This is the default template without a featured image

Blog Posts

If you include an excerpt via the document tab, your post will display that text in the header under the post title. I made an example post with an excerpt. Posts also display the category, author and post date in the header.

Pages

Pages do not have the excerpt option. Only your post title will appear in the header section when you use the default template in twenty twenty theme. The page you are looking at is a page without a featured image, so only the page title displays in the header.

Featured Image

You can set a featured image, via the document settings tab. That featured image will be centered, or sit on, the dividing line between the header and body sections of the page. See this example of a default page template with a featured image.