Coreldraw and Illustrator are the most used programs I think to make vector images and both have a "plot" option so in theory could be used to plot stuff.
I say in theory as a lot of plotters will not take commands or will refuse to install to these programms and requier their own software. This software will than have somekind of import option alowing you to use coreldraw and illustrator files.
The "briliant" sales trick here often is that you get the "standard" software with your plotter which allows you to do some basic stuff and need to upgrade the software to be able to use the above mentioned programms.
When I bought my plotter I was pretty naive and thought all software that alowed to make vector images could beused, as it turned out I needed to upgrade the basic software to do that (which would cost me 2,5 times what the actual plotter had cost me).
My advice to anyone buying a plotter ever since is make very sure what sofware can be used by default with it (as they will go out of their way to avoid mentioning this).
If the above prog's don't work with your plotter and you don't have an import option (or it's greyed out) I'm afraid you'd have to contact the manufacturer to find out how you can get that to work. Downloading software for plotters is next to impossible, its a too small market to have pirated software for it that works for any specific machine.