Once you create a notification on desktop website, follow the following steps:
1. Clone the notification
2. Change dimensions of the notification so that it looks good on mobile site. This can be done by changing width and height of the notification on visuals screen.
3. On Visuals Screen, go to Advanced Options>>Other Options>>Website(Drop-down)>>Choose mobile website.
4. Change targeting if needed.
To launch a notification exclusively on the mobile website, you will first have to choose the mobile website from the drop-down with website’s name on top right of the dashboard. Then create and launch the notification for that website.