Select a shape.
On the Format menu, click Fill.
Under Fill, click the options you want from the Color, Pattern, and Pattern color lists, and set the level of transparency you want.
The preview shows the effect of the settings you selected.
Note: If adding a gradient fill pattern has no effect, you may be working with an open shape, not a closed shape. Single lines and connectors are examples of open shapes in Office Visio. For information about drawing a closed shape, see Draw a closed shape with the Pencil, Line, Arc, or Freeform tools