The field identifier helps you to differentiate each field. It is most useful when there is more than one field with the same label in a form.
To turn on the field identifier option:
1. Navigate to the Settings page of your form.
2. Select the form logic tab.
3. Click on the switch below the sub-header - Do you want to see field identifiers?
Enabling this setting will allow you to see field identifiers when you go back to the edit icon of a field in the Builder page of your form, as shown in the image below. The field Identifiers can be renamed to easily let you distinguish between similar fields.
This option is best used when including the form logic feature in your form, working with multiple autoresponder messages or when working with the prefilling feature.