NTVDM stands for NT Virtual DOS Machine. It is not installed in Windows 10 by default. When you run a DOS program on a 32-bit Windows 10 OS, you will receive a popup to install NTVDM.

If your version of Windows is 64-bit, you're able to install both 32-bit and 64-bit software programs, so there are two different "Program Files" folders on your computer.

Identifying your system type is also important when upgrading. If you're running a 32-bit version of Windows, upgrading to 64-bit can help unlock the full potential of your computer.

If you don't yet have it setup, I've written a complete guide on how to setup and install WSL2 on Windows 10 and 11 you should check out first.