How to email completed form?

I am not sure if I have understood your question correctly. Do you mean to send the input data of form in email?

Please note that when you complete the form, you need to click on the "Submit" button of form. Once the form is submitted, the submission data will be sent in email as you have configured in form's notification email alert. The following guides should help you:

How to add notification email alert in form:   https://www.jotform.com/help/25-Setting-up-Email-Notifications 

How to change the recipient email address on which you want to send submission emails:   https://www.jotform.com/help/41-How-to-Find-and-Change-the-Email-Address-Used-for-Notification-Email 

Please note that you can also send an email to the user who submitted form by adding form auto-responder email alert in form. You may like to take a look at the following guide which should help you:   https://www.jotform.com/help/26-Setting-up-an-Autoresponder-Email

Hope this helps.

Do get back to us if you meant to ask something else.