TextEdit is a capable word processor but one useful feature is seemingly missing: page view. This shows how the text you’re typing will actually appear on the printed page. The default view simply wraps the text at the edge of the program window.
Well, it turns out the feature is there and has been so for years. Just click Format → Wrap to Page (or hit Shift+Command+W).
The zoom setting won’t change when you expand or shrink the window but if you have a trackpad you can zoom in and out using the pinch-with-two-fingers gesture. Alternatively, use the options on the View menu, or tap Shift+Command plus comma or period, to zoom in and out respectively, although there aren’t many shades of grey with this approach — you’re either zoomed in hugely, or not.
See below for an example first of wrap to page, then an example of its antithesis — wrap to window.
Curiously, when I tried to switched to page view on a Word document I’d opened in TextEdit, nothing appeared. Until I switched back to wrap to window view the TextEdit window was grey, as if no document was open.
Bonus tip: To insert a page break when in Wrap to Page view, hit Ctrl+Q and then Ctrl+L. (Ordinarily there’s no keyboard shortcut for this, although it’s an option on the Edit → Insert menu.)