I am trying to update Pages. The little wheel just spins for a long time. Is there something I need to do? I have no idea what original password I had when purchasing this item. I am betting it was different back then. What can I do?

The password that you used with your Apple ID when buying the app wouldn't have any effect on updating it now. It is the Apple ID that matters. If you have changed the Apple ID, you cannot update this app. The Apple ID used to buy the app is encoded into the licensed copy on your Mac and that is the only Apple ID that can redownload or update the app.

If you used a previous Apple ID to buy the app and you cannot recover that Apple ID, then your options are to use the app as is or delete the app and buy it again with your current Apple ID.

ASC - Late 2012 Mac mini, macOS 10.13.3;  Watch, 38 mm AL, watchOS 4.2.2; iPad Air 2 & iPhone 7+, iOS 11.2.5; TV 4th Gen, tvOS 10.2.6;  Airport Express