The email confirmations that site users receive can be set to address the user by name using personalization fields.
First, make sure that the user's name is a required field on the form:
Any field that you want to use to personalize the response email must be marked as "required."
Save the form on the "Build and Edit" tab, then open up the "Notifications and Redirects" tab. Scroll down to the Email Confirmation settings.
Select the checkbox labeled "Send Confirmation email to respondent," as well as the checkbox labeled "Include a custom message at the beginning of the email."
The "Personalization" button appears beneath the Email Subject line.
Click the "Personalization" button to bring up a window showing the available fields on your form that can be used to personalize the response email.
Click on a field to add a placeholder to the custom message for this email. It will appear in the custom message content area as "%[fieldname]%.
Whenever a form response is sent out, the system will replace that placeholder with the data in the corresponding field in that form response.