Unfortunately, as far as I know there is no free offline alternative to google forms.
We received similar requests from our clients (utility company managing technicians in remote areas with limited network, HVAC installers, etc.), so we decided to build a solution for this : Fieldeo (https://fieldeo.com/). Here how we made it :
- Easy to install on iOS, Android and even PCs/Mac
- Quick delivery, lower than 2 weeks (reuse of our backend architecture for each client)
- Input types of any type: we customize the fields in order to build great UX
- Pricing models based on your needs (fixed price or monthly ; unlimited users)
- Native Offline support
- Administration interface so the supervisor can validate the data before it gets exported
- Exports in multiple formats
Feel free to reach out if you want to know more and discuss the technical challenges behind that.