How to send a confirmation email to the form respondents?

You can send a customized confirmation email with a copy of the response when a user submits the form.

Step 1: Open your form in Google Forms. Click on the addon icon and click Peergateway.
Step 2: Peergateway menu will be displayed. Click More options.
Step 3: Peergateway sidebar widget will be displayed. Click Customize to open the Edit page.
Step 4: Edit page will open in a new tab. Click Orders.
Step 5: Click on the ⋮ More icon next to the Submitted status. Click Email respondent.
Step 6: Email notifications setup wizard will be displayed. Configure the "To" email by selecting the email address form field from the dropdown list and then click on the Next button.
Step 7: Configure the subject line for this notification email. You can enter a simple static subject line as shown in the screenshot below or you can use the form fields such as order id, name, order amount etc to personalize the subject for each respondent.
Step 8: By default, all the answers will be included in the email. You can customize this message to include other instructions.
Step 9: Submit a test response to check if the email notifications are working. If it works, click on the YES button. Otherwise, click on the NO button.