What is a good Emulator for a Windows Program

I need to load QuickBooks. What should I download for that Emulation. Thanks

You’ll need to use wine.
Wine takes a bit of work to get applications working with it, however there are some graphical utilities that help with this.

Playonlinux is the easiest to use, free and open source solution for setting up applications under wine.

Crossover Linux as a non-free commercial wine based solution, but it does have greater chance of success.

Or you could install Windows in a virtual machine.