There are two fields that appear on my form in preview but are invisible in edit mode. How do make them visible so I can edit/delete them?

If I understand you correctly, you are saying that there are 2 fields that is showing in the form preview. However, they are not visible in the Form Builder. Is that correct?

Please provide more details about the fields you're referring to. Also, if you can provide a screenshot, that will be very helpful. 

We'll wait for your response. Thank you.