One thing to know
Your data lives on the device you saved it on
These tools save everything privately in your own browser — nothing is sent to a server. That's what keeps your family's information under your control, but it also means your phone version and your desktop version don't automatically sync with each other.
If you fill something in on your phone and want it on your computer too — or the other way around — use Download Backup on the device you filled it in on, then Open Backup File on the other device. It takes thirty seconds and keeps both copies matching.
Those downloaded backup files aren't locked to this site, either — save them into your own Dropbox, Google Drive, or wherever you already keep things, and you can reopen and keep updating them from there. The tool doesn't need to be the only place your information lives.