How to save a form and continue later?

At the moment, whenever someone leaves the page, if they haven't completed all 29 fields, then they lose some of the information and automatically get taken back to the start.
Any assistance on this would be greatly appreciated.

Hello,

We have two alternatives for this request. 

#1- Auto-fill forms

#2- Session parameter method

Our user guides will tell you how to use them.

If you need further assistance, we'd love to help.

Thank you!

Regards.