Rearranging permalink structure

If I understand you, if you’re talking about permalinks for PAGES (e.g., About page, etc.), you can set the “permalink” for pages in the page-editor. It’s called a “slug” and you set it right below the title field where you edit/create your pages in the dashboard. In other words, on the edit screen, right below where you enter the title for the post or page, is the permalink for that page. For example, “Contact Us” as input in the title field, it is converted to a slug that looks like this: “contact-us”. You can subsequently edit it to another slug, but WP will not let you duplicate an existing one.

Yes, I’m familiar with how to change the slug in the area that you mentioned, but I’m referring to the ability to move that slug to the area before the root domain (rather than after)
For example, instead of “examp[lecom/newpage” I would like it to be “www.newpage.example.com” without creating a seperate subdomain, because I want it all to be within my pages section of the https://www.example.com wordpress.