If your device has SD card and your android OS is lower than 5.0, your notes will be backed up to the SD card. If your device doesn’t have SD card or if your android OS is 5.0 (or higher version), your notes will be backed up to the internal storage of your device.

Where are my notepad files saved?

The most likely default is under “This PC” – Documents, but if you open Notepad and then choose File – Open it will likely be first looking in the last location that you opened or saved a file.

Where are app files stored on Android?

For normal apps, there are stored in internal memory in /data/app. Some of the encrypted apps, the files are stored in /data/app-private. For apps stored in the external memory, files are stored in /mnt/sdcard/Android/data.