You can categorize your pages by assigning parent and child pages. Parent pages are top-level pages, usually with overarching themes, and are not assigned their own parent. Child pages are nested under parent pages.
Assigning Parent and Child Pages
To assign a child page to a parent, you should be in the editor of that page. Under the Page Attributes section (usually found in the right sidebar of the editor), use the dropdown menu to select which page you would like to assign as the parent.
In the classic editor, the parent attribute on a page creates the submenu links.
Another way to assign a child page to a parent is through the Pages section in the WordPress dashboard. Find the page you wish to edit and hover your mouse over the title. Click Quick Edit (second option), then select the parent page you wish to assign.
Viewing Parent-Child Relationships
Navigate to the Pages section in the WordPress dashboard. You can see parent-child relationships by the dashes in front of page listings.
Parent pages have no dash in front of their listing, whereas everything with a dash is a child page.