In one of three places, whichever you chose in Settings › Sync: a folder you picked (inside iCloud Drive, Dropbox, an Obsidian vault, anywhere), the app's own storage synced by iCloud, or on the device only.

They're plain Markdown files either way — nothing is locked in a database you can't reach.

Go to Settings › Sync › Choose Synced Folder and point dotMD at a folder inside iCloud Drive or Dropbox. Do the same on each device, choosing the same folder. That service handles the syncing; dotMD just reads and writes the files.

Your notes have not been deleted. If you're using a synced folder and dotMD can't reach it — a drive that isn't connected, a folder still downloading, or a permission that lapsed — the app shows "Synced folder unavailable" rather than your notes.

Reconnect the drive, or go to Settings › Sync and pick the folder again. Your files are untouched where they've always been.

Open Trash in the sidebar. Deleted notes stay there for 30 days and restore to the folder they came from.

Yes. Use Open File or Open Folder. When you open a file from outside the library, dotMD asks whether to keep a copy inside the app or edit it where it sits — either way you can edit it, and it'll remember your preference if you want it to.

Just paste. Rich text is converted to clean Markdown automatically — headings, lists, bold, code blocks and links all survive.

It works fully offline and there is no account. dotMD makes no network requests of its own — the one exception is Reading View, which loads the MathJax library to display mathematical notation.

Yes — under Settings › Privacy & Security, turn on Require Face ID (or Touch ID, or your device passcode) to open dotMD. The same section can hide note content whenever the app isn't in front, so it doesn't show in the app switcher.