As noted here, Video messaging in Desktop app - Product Feedback - Asana Community Forum, video messaging is currently available in the in-browser version but not yet in the desktop app.
A workaround to is to install Asana as an app using the Edge Browser.
Instructions for Windows:
- Navigate to Asana in Edge
- Select “…” in the upper right corner > Apps > Select Asana at the top of the list to install
You will then be able to open the in-browser version of Asana as if it were an installed app, while maintaining the web-version functionality, including video messaging.