Problem: You’ve been sent a .pages format document. No, I’d never heard of it either. Apparently it’s a sort of obscure equivalent of the old Windows .wps format, only it’s from word-processing software that ships with Macs. Like the old .wps format, nothing on earth will open it as intended — except its own native production software.
Solution 1: (defunct) It seems there used to be a Windows trick where you’d rename the .pages file as a .zip and there would be a preview.pdf inside that was usable. That trick doesn’t appear to work any more, at least with the newer versions of whatever Mac software makes .pages files.
Solution 2: (working)
1. Get the free LibreOffice, a version of the popular Open Office suite. The developers of LibreOffice are not afraid to incur the wrath of Apple by enabling .pages import. Install.
2. Open a new blank document in the Writer component of Libre Office.
3. Go: top menu bar | Insert | Document and insert your .pages file. Your document loads and appears, but looks like blank pages with a few lines of dots at the top of each page. The formatting has all been lost, but the dots are actually all the words scrunched up together.
4. Go: top menu bar | Edit | Select All | Copy.
5. Open MS Word or similar. Paste in what you just copied to the clipboard. As you’ll see, you’ve lost any fancy formatting there may have been in the .pages file, but at least you’ve got all the plain text and it’s in the right order, it flows and is editable.