Please find the below query regarding addition of Data in a Application. Kindly advice.

1.) We could add data table in an application while creating a application or adding the data class in Application Rule--> Case&Data tab-->Add data class.

Is there any other way to add Data type in an application.?

2.) Is is enough to import the data class in higher environment for moving the data table or should we import the class and add data class in the application rule?