For this to happen, you need to do the following:
Collect user email addresses on your Google Form.
Go to the Settings tab of Form Workflow.
Choose the Requestor Email (1) address from the drop-down menu.
Check the box Allow Send Back to Requestor (2)
Ensure you no not have duplicate column names. For example, if you are collecting user email addresses on your Google Form a column will be created on your spreadsheet named "Email Address". Ensure you do not have a question on your Google Form also named "Email Address". Make a slight change like "Email address".