Check this video https://youtu.be/A24qB58svOg?t=80 at 1:10
Similar application needs to be developed for Android and iOS using SLAM, blob detection, multiple object tracking, camshift tracking.
Basically in simple words what needs to be done is. User must be able to mark / highlight (draw lines, circles) on any object in the environment and then the marking (highlight) needs to stay onto the object that has been marked.
In phase 2, this same functionality needs to work on video + audio chat wherein the video feed of camera of person1 is also playing on person2's screen and both of them can annotate onto the objects in surrounding.
10 days for phase 1