Emailing Customer Completed Jotform

Please can someone remind me how to make sure the customer who fills in the form gets a copy. 

You need to set up an autoresponder email so that the user who completed the form will receive a confirmation email. Please refer to this user guide: https://www.jotform.com/help/26-Creating-a-Form-Autoresponder

Here are some related guides:
Explanation-of-Email-Notification-and-Autoresponder-Settings
How-to-Attach-a-File-to-Autoresponder-Emails

If you have any questions, let us know. Thank you.