Pages
How can I download an older version of Pages - compatible with OS 10.15.7
If you have previously installed Pages from the Mac App Store, then you may be able to get it from there again. Otherwise, you would need macOS Monterey or Ventura.
If true, then launch the Mac App Store on Catalina, sign in with the identical Apple ID as you used previously to install Pages, and press cmd+0 (zero). That will open a Purchase panel and if Pages appears there with an adjacent blue cloud icon, click that. A dialog will appear offering to install the last compatible version (11.1) of Pages for Catalina.