Default UI Menu: Modify/2D Boolean Operations/2D Intersect
Ribbon UI Menu:
Produces the intersection of two or more closed 2D objects, to form a region. Select two or more objects whose intersection you want to obtain.
Select Finish Selecting from the local menu or Inspector Bar.
The resulting object is one region. You can verify this by selecting the region.
You can select more than two objects, but they must all intersect one another.
Note: If you select objects that do not overlap, the result will be no objects (original objects deleted).