Pages File Converter
A client sent a .pages file and you are on Windows or Android. Drop it here to read it, then save it as a Word document, plain text or a PDF. Client documents are fine to use: the file is read by your own browser and never transmitted.
Why the usual fixes do not work any more
The common advice is to rename the file to .zip and open the PDF inside it. That only worked for files from Pages 2009 and earlier. Since 2013 a .pages file holds Apple's own compressed data plus a picture of page one, and no PDF at all. This tool reads that data directly, so it handles the files clients send today, and it still uses the built-in PDF when an older file has one.
It converts the text, headings and tables. Images, charts and exact page layout are not converted, and it tells you when a file has any. For a filing or anything where layout matters, ask the client for a PDF.
Ask the client to send it properly next time
Copy this and send it back. It covers iPhone, iPad and Mac.