Your two options for converting a Pages document to PDF are a) open a Pages document in Pages and then File menu > Export To > PDF, and 2) as before, but this time File menu > Print > PDF > Save as PDF. In either option, choose where to save that exported PDF.
Neither option in the first paragraph causes the wait-state spinning color wheel which implies that there is some unexplained contention between your conversion effort and the operating system. Reboot your Mac, and apply one of the options from the first paragraph and see if you get a proper PDF from that effort.