To control this headset will have a touch control panel, using voice over Siri and gestures of the head. This headset is only a part. It is reported that Apple is also creating a new OS called "real operating system" for headsets and a dedicated application store for AR applications.
This plan sounds very similar to what Google has done with the Daydream VR platform, including a controlled Daydream View VR headset, and a Google Play Store version exclusively for VR applications.
No matter how good the AR headset idea is, remember that Apple can throw it away at any time, look at the Titan self-driving project. Mr. Cook also said that AR glasses will not be released soon. 'We are not in a hurry to be the first to create the best user experience.'
Anyway 2020 is still far away so please enjoy iPhone X and use VR and AR applications on it
See also: iPhone X can be the foundation for Apple's smart glasses
What is AR? What is VR? Are these two technologies similar and different?