Later this month, you will be able to autosave your progress in a Google Form or Quiz for 30 days after your last edit. This highly requested feature prevents loss of data if you lose internet connectivity, need to switch devices, or don’t have time to complete a form or quiz. You must be signed into your Google account to use this feature. 

Owners and editors can remove the ability to autosave for individual forms and quizzes. To remove this option in Google Forms:

• Click the Settings gear. 
• Choose Presentation.
• Select Restrictions.
• Click the option to Disable autosave for all respondents.  

For more information, see Your progress is automatically saved as you respond to forms and quizzes.