Combine shapes or paths
As you might expect, when you combine paths or shapes, you effectively create a single object. For information about how to join open ended paths, see Add or remove a point on a path.
After you combine objects, the result might be a compound path, depending on how the original objects overlapped. Compound paths have the added benefit of being able to release them long after the option to Undo combine action is gone. For more information, see Make or release a compound path.
You will not be able to edit properties that are specific to a shape (such as the corner radius of a rectangle) after combining. Also, if a style was applied to the last selected object before conversion, the properties of the combined path will be reset to the defaults for a path (no fill brush, and a black stroke).
Select two or more paths or shapes on the artboard. (To select multiple objects, hold the CTRL key.)
On the Object menu, point to Combine, and then click one of the following:
To combine all shapes or paths into one single object, click Unite.
To cut the shapes or paths up based on where they intersect but leave all the pieces intact, click Divide.
To keep the overlapping areas of the objects and remove the nonoverlapping areas, click Intersect.
To keep the nonoverlapping areas and discard the overlapping areas, click Exclude Overlap.
To cut all other selected shapes out of the most recently selected shape, click Subtract.
The resulting object will replace the last object that was selected before combining, adopting that object's properties.
Two shapes before combining