How do I email someone on my form?

You meant you want the form to send a confirmation email to the form respondent?

You can do this using the form Autoresponder E-mail.

User guide: Creating-a-Form-Autoresponder

OR

If you meant you want the form to dynamically send the appropriate email to an intended recipient base on an answer provided in the form, you can also achieve this using conditional email feature.

User guide: How-to-Send-Email-Based-on-Selection

You can also assign the person's email in the Recipient E-mail field so that the form email will be sent to that email address.

User guide: How-to-Find-and-Change-the-Email-Address-Used-for-Notification-Email

Hope this help. Let us know if you need further assistance.