How to Create a Clipping Mask in Adobe Illustrator
A clipping mask created in Adobe Illustrator allows the artist control over what is seen and what is hidden from view on the artboard. This is accomplished by placing a vector shape on the page that acts like a window. The image that falls within the borders of the vector shape can be seen; the image that falls outside the shape is clipped, or hidden. This is beneficial when you don't want to delete parts of the actual art. Once the clipping mask is placed on the art, it can be moved and edited so that different parts of the art are visible.
Open the Illustrator document that contains the objects you want to mask.
Create or draw the object you want to use as the mask that will clip parts of the image. Select a drawing tool and hand draw a shape or select a graphic or symbol. Only vector objects can be clipping paths; raster images cannot.
Click on the "Layers" palette. Move the clipping path you just created above the layer that contains the object you want to mask.
Click the "Selection" tool in the Toolbar. Select both the vector image and the clipping path. Select "Object" from the main menu, then scroll to "Clipping Mask" and choose "Make."