You can designate a saved path as a clipping path to make part of an image transparent when exporting the image to a page-layout or vector-editing application.
Create a new path in the Paths palette before you begin drawing to automatically save the work path as a named path.
To create a new work path:
Select a shape tool or a pen tool, and click the Paths button in the options bar.
Draw additional path components if desired. You can easily switch between drawing tools by clicking a tool button in the options bar. Choose a path area option to determine how overlapping path components intersect:
Add to Path Area to add the new area to overlapping path areas.
Subtract from Path Area to remove the new area from the overlapping path area.
Intersect Path Areas to restrict the path to the intersection of the new area and the existing area.
Exclude Overlapping Path Areas to exclude the overlap area in the consolidated path.
Use the following keyboard shortcuts while drawing with a shape tool: Hold down Shift to temporarily select the Add to Path Area option; hold down Alt (Windows) or Option (Mac OS) to temporarily select the Subtract from Path Area option.