Hi Rich. I'm Greg, 10 years awarded Windows MVP, specializing in Installation, Performance, Troubleshooting and Activaiton, here to help you.
The App hasn't been working for awhile so I've been helping many install iCloud which works better than the app once you get it installed. There can be install glitches though so I'll cover those, but first here's how to install iCloud and its features:
https://support.apple.com/en-us/HT201391
https://support.apple.com/en-us/HT204363
https://www.laptopmag.com/articles/icloud-email...
https://support.apple.com/en-us/HT205323
Troubleshoot Installation:
https://miapple.me/fix-icloud-for-windows-10-re...
http://smarterware.org/2019/04/cant-install-icl...
https://windowsreport.com/cant-install-icloud-w... (Avoid ad links which intrude into editorial copy, especially avoid Restoro and Reimage ads)
https://www.errorsolutions.tech/error/icloud-fo...
https://appletoolbox.com/icloud-sync-issues/
As to the App not working, If you want to report this to Microsoft use the Feedback Hub app in Start Menu where developers are tasked to process consumer feedback. They will not even see it here. This is a tech forums staffed mostly by volunteers trying to help others with your problems.
If you want to post back a Share link from your Feedback here others who see this thread can vote it up and add to it.
I hope this helps. Feel free to ask back any questions. Please report back results for all steps given so I know what else to suggest if necessary.
______________________________________________
Standard Disclaimer: There are links to non-Microsoft websites. The pages appear to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.