In almost every scenario pages to docx conversion represents export of Pages documents to Word format and many people are actually looking for a way how to convert pages to word. Mac users can achieve this pretty easily using Pages, but you can always try iWork for iCloud online.
On Windows, a viable alternative would be to install the latest version of LibreOffice suit that apparently supports some versions of iWorks documents. This may not always be perfect, and some formatting may be lost during the conversion process but is likely the best option to convert .pages to .docx in Windows.Open PAGES file Open DOCX file
An on-line version of Pages, Numbers, and Keynote
Full-featured word processing and desktop publishing tool from LibreOffice suite
Mobile version of popular word processor from Apple
A word processor and layout tool marketed by Apple