Currently 10 July, 2020 the option to add a note in the hosting calendar is not working in the Android Airbnb app.
To add a note hosts should switch to the full website version of Airbnb.com.
How to add a calendar note:
- Go to your Calendar on airbnb.com
- Click a date to select it, or click and drag your cursor to select multiple dates
- Click Add next Private note on the panel on your right
- Click Save