Vector masks can be quickly created using paths. Go to the various shape tools in Photshop and select the path option in the top left (not shape or pixel). Create a design on top of an image, this is a path so you won't see the item appear in the layers panel but you will see it in the paths panel. With the path selected using the 'mask' button in the control bar to change the path quickly to a mask. You can then manipulate the artwork using the direct selection tool. You can then see more or less of the underlying layer andif there is only the background you will see the transaprent background.
Create a path with the current shape tool such as the ellipse or rectangular tool or custom shape tool and use top left as path. Go to the layer menu and vector mask and select current path and again, the layer wil be cut to the design. If there is only a background then you will see less of the image and more of the transparent background