Apple Pages word processor has default export function to PDF, so this is probably the main way how to achieve pages to pdf conversion, but you would require some Apple device for it.
Some older versions of .pages documents may also be opened using LibreOffice Writer, which can be potentially useful for users without Mac or iPhone. There is the possibility of using iCloud to convert .pages documents to Microsoft Word formats or you can use one of the online conversion services.Open PAGES file Open PDF 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