Setting up administrative fields on form

is there a way to add fields to the survey which we can use to update forms for internal operations, for instance, when someone completes a step in our sales funnel?

and then filter for surveys that have that field checked?

Yes, it is possible to hide fields on forms (right click on the field > Hide). The fields will be accessible in submission edit mode.

There is also a Hidden Box field (displayed only when the submission is edited via submissions page) type available, please follow the next guide.

How to assign a status to submissions

If you need any further assistance, please let us know.