Unlike posts, which are listed by date and can be tagged and categorized, pages are added to your site’s menu and can be organized by hierarchy. You can create top-level “parent” pages that are visible in the menu and lower level ‘child’ pages that only appear in the menu when you mouse over the parent page.
For example, if you were adding a services section, you’d create the main services page as the parent page.
Then you’d add child pages for each of the services you provide.
The Parent dropdown in the Page Attributes box is how you make a page a child page.
When you create your site’s menu you’ll be able to easily arrange pages in the exact hierarchy you want, and the child page will appear when you mouse over the parent page on the menu.
Having a page hierarchy makes it easier to find your pages later when you have dozens of pages.
You can also create page hierarchy using the Appearance > Menus section, using the simple drag
and drop functionality.