To open a file with a specific application via Windows Terminal, use the command start application.exe "file path" in CMD, where application.exe is the executable name of your application and "file path" is the full path to your file. In PowerShell, use Start-Process -FilePath "application.exe" -ArgumentList "file path". This explicitly specifies the file path to the application and the argument list with the file you wish to open. Ensure the application can open the file type you're working with.