Featured Images: The featured image (formerly known as the post thumbnail) is an image that represents a post which might be shown by itself, depending on how a theme displays posts.Excerpts: An excerpt is, as the box says in WordPress, a summary of a post. Excerpts are shown with a continuation string. By default, ‘[...]’ is appended to your excerpt text, which is 55 words long.

Comments are readers’ responses to posts. They are written in a small form on a post or a page and, once approved, are displayed in a list below the post. 
Whereas, Trackbacks are automated alerts that someone has referenced a post or a page on their own site. It lets know that conversations are taking place elsewhere about something the author wrote.

Page attributes are arranging the pages into filesystem-like hierarchies by making them children of parent pages. In the Attributes box on any single page’s Edit screen, we’ll be able to select another existing page as the parent which in turn, have another parent, and so on.

Posts are shown in a chronological sequence on a single page, such as your home page or an archive of posts from a particular date and can also be tagged or filed into category.
        Pages are generally not grouped in chronological order. It will appear on its own screen. Anyone can create a list of pages using a widget or a menu.
        Moreover, comments are allowed in post but in page it’s not allows.

In WordPress we can change site's appearance by using customizer, widgets, the menu manager, and uploading custom hearer and background images.
go to Appearance > Themes and click Customize button under active theme.