Can i put in hidden fields that only I can see when form is sent?

Can i put in hidden fields that only I can see when form is sent?
Meaning elements that get added to the form like a blank text box, or check boxes?

You can hide fields on your form and be able to view it when you edit the submission. You need to add a GET FORM PAGE URL widget to achieve this. Please see this guide on How-to-Show-or-Hide-Fields-on-Edit-URL.

Please try that and let us know how it goes.