All data collected by the BibleWork app is stored on the device. The data may be stored on other systems too depending on the settings for cloud storage or backups using iTunes or similar methods.
The data collected by the BibleWork app is solely used to store the data, which is provided by the user, on the device. This data can be erased by removing the corresponding items in the app or by removing the app from the device.
The BibleWork app stores the data, which the user enters while using the app.