Can I create a game in UE4 for UWP Windows 10 Platform for the Windows Store?

I have a developer account with Microsoft for the Windows Store, which requires apps to be compatible with UWP for Windows 10. Can I ship games built with UE4 to the Windows 10 Store? Is there a way to generate an .appxupload project file from UE4?

Yes but currently is not avable in main build of UE4, you will need to download from github and build special version of UE4 made by Microsoft that has UWP support implemented:

https://forums.unrealengine.com/development-discussion/engine-source-github/90679-unreal-engine-4-is-available-for-win10-uwp-app-dev-now

I also don’t think Epic officially support it, you most likely get better help in Microsoft forums pointed in post above, but nothing wrong happen if you post quastion here too, maybe some user will be able to help in your problems related to UWP as long as it relates UE4 side of things.