save form before submission

If you need a copy of the submission for yourself or anyone submitting the form, Email Notification and AutoResponder should do the job for you. For editable submissions, simply add the edit link to the email and user will be able to click the link and access the form with all the previous entries- Let-Users-Update-Their-Form-Submissions-at-a-Later-Date.

If you need something more complex like preserving entries and allow user to continue later, here are some more detailed guides:  How-to-Save-Forms-and-Continue-Later, Enable-Auto-Fill-Feature-Save-Form-Entries-to-Continue-Later