If you want to pass a unique ID on a form field or into the email to identify each of the form submissions, you can use the {unique_ID} smart tag, or in the default values for the form field, you can choose the Unique ID parameter from the available value parameters.

Unique ID as Form Field’s Default Value

Unique ID in the Email (As a smart tag)

Go to Form Settings > Email. Now, choose the desired email notification, and on the Email Message section, add {unique_ID} smart tag.

Check out all the available smart tags in the Everest Forms.