By copying a data file to a USB flash drive?
Anecdotal, but I don’t think many non-tech users have used a flash drive in the last couple years.
They could choose a Saas service (Dropbox, iCloud, WinBin/whatev). Hell, I'd probably do this but encrypted where I like.
In this way you'd have the data storage decoupled from the app so the choice would be there.
How would non-tech users handle backups?