Forms notify a specified person by email when an entry is received. To notify the site administrator, click the Forms button, and hover under the label of the form you wish to change to make "Edit" appear, and click on Edit. On the new screen, hover over Form Settings and click Notifications.
A notification message is required. {all_fields} is helpful as an admin notification because it sends all the information the registrant entered.
To check your site's admin email, navigate to Settings, then to General Settings. The email listed under Administration Email Address is the email address represented by {admin_email}.