Using the controls in the Drop Shadow tab of the Modify dialog box (Item menu) or the Measurements palette, you can customize how a drop shadow looks, including its distance from the item, size in relation to the original item, offset, angle of light source, color, shade, opacity, blur, and more. You can also synchronize the angle with other drop shadows in the layout, making it easy to maintain a significant light source throughout a layout and making drop shadows seem more natural.
Choose the Drop Shadow tab in the Measurements palette
Check Synchronize Angle when applying a drop shadow to an object.
This option allows you to easily change the angle of one drop shadow and apply that change to all the drop shadows in the layout.