How to sync with Windows using iCloud?

First, you'll need Password Safe for Windows.

Then install Apple's iCloud Windows app and enable iCloud Drive.

If you already have a safe on your PC, move it to the pwSafe subfolder in your iCloud Drive folder. If you wish to open a safe you already have on pwSafe for iOS or Mac, then open free Password Safe app and browse for your safe inside the pwSafe subfolder in your iCloud Drive folder.