If you are a PRO user you can attach a video to your conversation! To do this you must either first post your conversation or save it as a draft first to attach. Once you have a draft or it's posted you will have under the draft editor or the edit button on the top right of your conversation the option to attach a file. If you upload a MP4 video file under 100MB it will be rendered as a viewable video and same with audio files. When you upload a video file we will render a thumbnail client side and send that along with it. Videos use a lot of storage and same with raw images or other files and that is why you need to have PRO to do so.