How can I delete a page in the Pages document?

In a Pages page layout document, every page is also a section and you can simply right-click on any thumbnail to remove that page. However, this will not work if the document is a default word-processing layout document.

Intro to word-processing and page layout documents in Pages on Mac - Apple Support

OH-MAH-GAHD! That worked! I've been bugged by that same issue for years. Thank you so very much for this simple solution, VikingOSX. You may be a Viking, but you are also a gentleman and a scholar. An Apple scholar.

You do not have a page layout format document. It is a word-processing layout document and that negates my original interpretation that you had a page layout format document. Thus, you cannot remove a page thumbnail in a word processing layout document or risk wiping your document.

Instead, you click on that third blank page thumbnail, and on that page, you press shift+cmd+i to Show invisibles. If what you see are one or more paragraph marks, just backspace until the blank page thumbnail disappears. If it is a blue line across the page, double-click on it to select, and then backspace to delete that artifact and hopefully the page itself.