AK Notepad help
My name is Rose and I work for Snaptic (we develop AK Notepad).
We store your notes locally on your phone. We do not store your notes on the SD card. We choose not to store notes on the SD card for privacy concerns; any app on the phone can access files on the SD card. When they are stored locally, only AK Notepad can access the files.
In the future, you can go into settings and export your notes to your SD card. I highly advise deleting the copy of the .txt file after you're finished doing whatever you're doing with your notes.
You can also sync and backup your notes for free to Snaptic.com. You can create an account directly from the app. Syncing to Snaptic.com will also back up any reminders that you set on notes.
I hope this helps! And sorry about the missing notes. We'd just like to make sure we take as much effort to prevent personal information from being accessed by any app on your phone.