By default (no sync):
Your entire budget lives in a single, encrypted database file that stays inside Monefy’s private sandbox on your device. Other apps—and even Monefy’s developers—can’t read it.
If you enable cloud sync:
The same encrypted file is merely copied to a folder called Apps / Monefy in your own Google Drive or Dropbox account. Only people who already have access to that cloud account can see it; Monefy’s servers never touch the file.
When you create a manual backup:
The file is saved to whatever location you pick in the iOS Files app or Android file picker. Anyone who gets a copy of that file plus the app could restore it, so store backups somewhere secure.