A new patent has emerged that points to this Apple intention.
You might think you only need your fingers to interact with the iPhone, but judging by the latest patent submitted by Apple, it looks like something that might be feasible in the future.
As 9to5mac says, the patent describes a method for identifying the position of a ‘pen’ on a touch screen, with the device detecting the approximate position and activating small sensors for more accurate detection.
It could be thought that the fact that the patent did not specify the iPhone meant that it was the iPad but, as you can see from the image above, the shape resembles a smartphone. This means that the Apple Pencil may be compatible with the iPhone but, until Apple’s confirmation, it’s just speculation.