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# identifier

The string that you use internally to identify the action.

```
var identifier: String? { get set }
```

## Discussion

The system passes this string to the [`application(_:handleActionWithIdentifier:for:completionHandler:)`](/documentation/UIKit/UIApplicationDelegate/application(_:handleActionWithIdentifier:for:completionHandler:)) or [`application(_:handleActionWithIdentifier:forRemoteNotification:completionHandler:)`](/documentation/UIKit/UIApplicationDelegate/application(_:handleActionWithIdentifier:forRemoteNotification:completionHandler:)) method of the app delegate when the user chooses the action.

---

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