I'm assuming you mean the flourishes/background design you see on bills? Like this monopoly bill:
You already have the
Rectangle Marquee Tool and
Elliptical Marquee Tool (Keyboard Shortcut

hift + M). Simply start out with the basic shapes: The actual rectangle and oval upon the bill. Then using free brushes from
Brusheezy you can add embellishes, repeat the layer and set it to a lower opacity to blend with the bill. Since you have Adminstrator Status, I will assume you are familiar with Photoshop Settings.