How do I add someone to receive an email when someone signs up on a form?

You can do this in the Emails wizard. Here's how:

1. In the Form Builder V4, click the "Settings" in the top menu. Go to the "Emails" section. Select the Notification and then click the "Edit" button. 

2. Go to the "Recipients" tab. Here you'll see the Recipient Emails where you can add or remove a recipient.

3. Click the "Save" button when you're done.

Related user guides: 
https://www.jotform.com/help/25-Setting-Up-Email-Notifications
https://www.jotform.com/help/39-Send-Notifications-to-Multiple-Recipients

Hope that helps. If you have any questions, let us know. Thank you.