Your (new) Windows PC doesn’t support DOS applications anymore.
Previous Windows 32-bit versions included NTVDM, facilitating DOS programs to run. Windows (10/11) 64-bit is now the norm: Starting a DOS program will display a popup it can’t run:
Microsoft dropped 16-bit (and so DOS) support in 64-bit Windows versions!
To find a version for your PC, check with the software publisher.
That probably doesn’t help: The DOS application could be developed by yourself, a company not supporting it anymore, or even out of business. Despite eventual Windows versions/alternatives, you may prefer using that application for various reasons and time to come.

One option is to install a virtual Windows 32-bit system. The setup can however be daunting. To 'only' run that DOS application, its practical use overkill and cumbersome.

vDos lets you conveniently run DOS applications by emulating an extended DOS PC in a window. Not in a nostalgic manner, as once in DOS or NTVDM, but optimized for modern Windows. vDos itself runs on Windows 7 or later, 32 and 64-bit. It will be the most adequate solution for using productive DOS programs.

If you however don't still use an essential DOS application, but want to play/experiment with DOS. Its command prompt, programs or games: Forget about vDos, it is not meant for you!
vDos highlights.
DOS applications start almost instantly in a scalable window and crisp TTF font (in text mode). Actually delayed (the almost) until it accepts input. No 'intro' of DOS startup commands, just popping up the application.
Mature and no-nonsense, focuses exclusively on serious end-user programs, setup yours easily. No complex configuration to load drivers, set file handles, keyboard layout, language character set…
Run multiple DOS applications (simultaneously), if needed with their own specific configuration. No conflicts with eventual Windows NTVDM instances running alongside (like in a mixed network).
Also prints to Windows-only (GDI) printers, for instance a virtual printer to produce PDF’s.
Reliable, its DOS file system is (a subset of) that of Windows. No internal file caching/buffering corrupting data.
Secure, confines DOS applications to assigned local or network directories.
Network support with (verified) record locking, required by multi-user DOS applications to function reliable.
Copy/paste Windows text to DOS and vice versa, transparent conversion of Windows Unicode-DOS ASCII text.
Fully portable, small footprint and little impact on Windows resources.
vDos by JHM Schaars  -  The Netherlands  -  CoC 09103086  -  VAT NL001103274B12  -  No cookies