Augmented reality head-mounted displays (AR HMD) enable visual notifications directly into the user's field of view (FoV) to perform dual-task. However, research on the efficient presentation of notifications when communicating with a virtual avatar in augmented reality (AR) situation has been insufficient. For efficient AR notification presentations, it is necessary to understand where to display notifications without interfering with virtual avatar communication. We investigated two coordinate systems (world-fixed and display-fixed) and eight positions for AR notifications when conversing with the virtual avatar. Results showed that the top-left position increased response time and task load. Our study contributes as a cornerstone to designing AR notifications in communication with virtual avatars.