The form’s preview option is only to see how the form will look; it doesn’t create new entries when you submit from the previewed form. You can, however, easily test your form at any time from the live installation.
Email notifications can be enabled within your form settings by checking the box labeled “Receive email notifications?” and entering in one or more email address. The emails can simply let you know there’s been a new entry, or it can include the submission’s field data by clicking the “Include details?” box that appears after email notifications have been selected.
Once live, any form entries are automatically stored in the entries folder for that form, and are hosted on a secure Microsoft Azure Cloud Server. You can view all your entries in this folder at any time, even if you have email notifications enabled.
Disclaimer: I’m a developer for Cognito Forms.