Some simple Visio shapes, such as the Line, Rectangles, Ellipses, and some SmartShapes have a basic format to them. Visio enables you to enhance these shapes to provide the visual identity necessary to get your point across by formatting them. You can format the Line, Fill, and Shadow attributes, and add text.
Formatting line styles is a common practice to help differentiate shapes. Line styles can be a variety of patterns, weights, and colors. Follow these steps:
From the Standard Toolbar, select the Rectangle tool.
In your drawing document, click and drag to draw a rectangle.
Verify or Select the shape to format it.
On the Format menu, click Line. The Line dialog box appears ...