ADD A SAVE FEATURE

You can enable the Auto-fill feature and this will save the filled in form in browser, as long as you don't clear the cache, and for the "time to live" defined:

Please also enable "save on data changes" so that new changes get saved.

Another option is to use the "save forms to continue later" method that will enable user to continue filling in the form later from any location, with same browser or not. It's a more complex solution but it offers a more stable solution.
You can see here more details:

https://www.jotform.com/features/save-and-continue/? 

Let us know if we can assist you further.