Hi, is the design just for the front or would you like some on the back as well?

You can do either, whatever you feel works best for your particular design.

What program would you like the T-shirt design to be made on?

Some type of vector program is probably best/easiest, otherwise it needs to be done in a photo shop type program at 300 dpi resolution(or greater) and canvas size needs to be the actual size the image is to be printed.