When to use
To show how many notifications a user has.
To show simple information that doesn’t require interaction (such as the type of transport).
When not to use
For anything longer than a very short number or one icon—use a badge.
To include an action—use a button (a circled button has a similar look with an action).
Include nonvisual info
Look & feel
Choose type based on urgency
Info: Subtle, useful for counters. Use when you just want to show users that there is something to see but action isn’t necessary (such as a wish list).
Critical: Grabs attention. Use when the notification requires real action from the user.