The iCloud Drive title in my Mac's Finder window, shows a cloud symbol on the left side, and a circle on the right side with a segment not completed. I am having problems uploading Pages documents on my Mac to iCloud that can be read on my iPads. I can use Pages on the iPads, and the documents show on all my devices, but when I write them on my Mac, they don't always show on the iPads. I have made sure I am signed in to iCloud from each device. Any thoughts?
This sounds like an iCloud sync issue on the Mac end, not the iOS end. I know you said that you are signed into iCloud on each device, but make sure you are signed in with the same Apple ID. If you are signed in with the same Apple ID, then go to System Preferences -> iCloud -> iCloud Drive, and make sure Pages is selected on your Mac. For more information, see this help article from Apple.