Is Xcode and MacOS needed on our local PC for creating iOS app

do i need to make app from xcode on my local PC and then upload or i can just upload the cordova files and voltbuilder will automatically give me apps for both iOS and Android?

No, Xcode does not have to be installed locally. (Good thing - Xcode does not run on Windows).

You just have to upload the files and VoltBuilder returns iOS and Android executables.