Can I see what is stored on my iCloud
can I login to my iCloud account and see what has been backed up
Question marked as
It depends on what you mean exactly. If you are referring to your iOS backups that are done either automatically (by having iCloud Backup turned on) or manually (by going to Settings>your name>iCloud>iCloud Backup>Back Up Now), then you cannot see what is contained in them. You can see what you have selected to back up by going to Settings>your name>iCloud>Manage Storage>Backups>tap on the device in question. That will show you all of the various apps that you have selected to back up. In addition to the data for those apps, iCloud also backs up the following:
What does iCloud back up? - Apple Support
If you mean that you want to see what data you are syncing to iCloud, you can see that actual data in the app that is syncing (Contacts, Calendars, Notes, Reminders, Photos (if you are using iCloud Photos), files in iCloud Drive under the Files app, etc.), or you can go to iCloud.com via a browser on any computer and see the apps and their contents there.
Best,
GB