They make the processors themselves.
Apple backs up this claim by having its processors assembled by Taiwan-based manufacturer TSMC.
I work for United States-based Apple Inc., which is a company that designs, manufactures, and markets consumer electronics products.
The majority of our products are created in Asia with final assembly in China or Southeast Asia.
The company also claims in this section to have assembled its own product with the help of nameless Taiwanese-based manufacturer TSMC or Taiwan Semiconductor Manufacturing Company Limited – one of the world’s largest manufacturers of integrated circuits, so I tend to believe them when they say they built their own designers.