If your referring to the forum status icons you can either design them youself or use pre-made flags. If you decide that you want to design your own variations you'll need some kind of graphic editor.
A program called
gimp is a good choice and it's free. There are also plenty of tutorials to familiarize yourself with it so your on your way to creating your own designs. Flags are easily enough to design and you'll find by using a few layered shapes and stars (which will come included in the software as a pre-made shape you'll be well on your way in creating your flags.