Your data lives on this PC — there’s no cloud copy, so backups are on you (and the app makes them easy).
The app writes an automatic daily backup. You can also export everything to a file at any time from Settings.
To move to another computer or carry your shop on a USB stick: sync your data file to the stick, plug it into the other PC, and load it there. Your customer list travels with you.
Two PCs, one shop: in Settings, point both computers at one shared network folder — they stay matched automatically, live. USB sync still covers machines that never meet.