how to download to PC from icloud storage on ipad my doc files

If you are attempting to access or transfer data via iCloud, using your AppleID account, you can install iCloud for Windows - which, for Windows 10, should be downloaded and installed directly from the Microsoft Store:

Download iCloud for Windows – Apple Support

Set up and use iCloud for Windows – Apple Support

An alternative to move data between your iPad and Windows PC is to install Apple iTunes on your Windows PC. Again, for Windows 10, iTunes for Windows should be obtained from the Microsoft Store:

Download and use iTunes for Windows – Apple Support