Any phone that supports SMS, even old cellphones, can communicate with iPhones and appear in green bubbles. iPhones use Apple's iMessage system and display a blue bubble around the text.

The history of blue and green iPhone message ... a seamless and free way to send text messages, photos, videos, and more. The color difference of message bubbles was a visual cue to distinguish ...

One thing that is definitely not "cool," it seems, is having a green text bubble. On Apple's iPhones, instead of conversations appearing in the typical gray and blue, text messages from non-Apple ...