Is there a way to enable Steam VR or Unreal game to launch in VR?

Wish to play games made w/ Unreal in VR. How is that done?

If Dev disables VR launch, is there a way to enable it or force it?

How does a modder know if a VR mod can be made for a game?

How can VR mod be made for any game?

What games have VR mod?