Alerts are banners that communicate a message with a severity attached to it. They grab the user’s attention to provide critical information needed in context.
Standard alerts are used in the context of an application either in the content area itself or within components.
There are four different sub-types of standard alerts success, info, warning, and error
App-level alerts are used in the global context of an application. They are placed at the very top of all content and navigation.
There are four different sub-types of app-level alerts: success, info, warning, and error.