How to save a partially completed form and come back to finish it?

My form has a lot of information to provide and users are finding once they start, they have to finish it or lose their work.  Is there a way for a person filling out a long, complex form to save it and come back to it without submitting it for final review?  

Yes you can use the save forms and continue later feature:

How to Save Forms and Continue Later

I created a demo for you:

https://form.jotformpro.com/72085478458974

On my demo page you submit your email. Its used to generate a session.

When you fill in the first page of your form and press the next button it saves the page.

And you should get an email with the continue link in your email.