This isn't going to get you useful information, because the next question is, what is your aim? What do you need the VM for?
What type of virtualization?
If you're asking for this, then you'll know in much more detail what you need it for, and then you'll be in a position to investigate.
A VM is possible with Linux, google 'linux KVM'. However, it's not the same as on a PC and it won't run PC applications. You need a reasonable technical reason for it in order to use it with ARM. It might not even be the right solution, because you have not specified why you need it..
Well my intention is to run windows 10 on the raspberry pi 4 B.
Searching I was disappointed to find that there are only unofficial builds of Windows 10 on ARM that run on the RPi 4, so I'd probably look into another ARM64 board (more of a laptop honestly) with official builds if you want the full Windows 10 on ARM. Which would be nice because Windows 10 on ARM have x86 emulation already built in, assuming that's the reason why you want a VM on the RPi?
If you just want a Windows environment to run your own programs in on the RPi then there's Windows IoT Core, which was far as I can tell have no (official) support for the RPi 4 yet (or even the RPi 3 B+?).
If you really want to run a VM on the RPi 4 I'd look into QEMU (you can install aqemu from apt on the RPi to get an easier to use graphical interface for QEMU). Sadly almost everything I find searching for Windows 10 on RPi 4 QEMU are guids on how to run Rasperry Pi OS on a Window PC. This solution will probably require a fast external SSD to be usable.
Good luck with your endeavors!