AT&T and Sprint Galaxy Note 8 updated with AR Emoji and Super Slow-Motion video
In the United States, the most recent carriers that released a Galaxy Note 8 update which adds the features mentioned are AT&T and Sprint. According to the changelog, the update also brings the September security patch to Samsung Galaxy Note 8, along with new camera functions: AR Emoji and Super Slow-Motion.
The update has started to make its way to AT&T and Sprint Galaxy Note 8 units in the U.S. only recently, so it will probably take a few more days to reach all devices. Even so, you can manually check if it's available by heading to Settings / About device / Software update.