As this app does not store data anywhere but on your device you need to export your data as backup from time to time to prevent data loss if your phone breaks or gets lost. Additionally you should backup the app media folder if you add media to flashcards.

If you export all filing boxes an output file is created and additionally you can share the backup (e.g. by sending an email to yourself) after the export finished. If you export a single filing box the share dialog is the only option.
