How to make the fields in print preview editable (for data entry).?

Good questions. Our forms are very intense; some have over 500 fields per form. We can not change the forms; they are copyrighted. Our users expect to be able to fill in the forms directly. They do not want to have to jump back and forth between the data entry screen and the print preview to see how the data looks on the form. From our perspective, we would prefer not to have to layout the fields for every form twice, which could lead to mapping errors. We support over 850 forms.

"They do not want to have to jump back and forth ... to see how the data looks on the form."

Interestingly, this issue goes all the way back to DOS vs Windows, decades ago. When we first started providing software for filling out forms we used a WYSIWYG interface. First for the Mac in 1984 using a software package called Megaforms. Later when Windows 3.1 came out we did the same for pcs. Prior to that time nearly everyone was using DOS. Fortunatley for us times changed and people started using WYSIWYG forms.

Then the "mobile first" craze came along with responsive layouts. We are fine with responsive layouts. They just do not work very well with intensive forms that require a lot of fields in a small amount of form space. Our users do not want to flip through 10 or more screens to do what they were achieving on one screen. There are a lot of businesses in numerous vertical markets that require the gathering of large amounts of data on letter size forms; for example: law offices, real estate agencies, hospitials, insurance agencies, government agencies, etc. These forms are not going to be filled out on an iphone or an android device. Ninox already offers some nice layout options. Perhaps they could add one more, a WYSIWYG form. I think it would result in the sale of more Ninox licenses.

For clarification, when I refer to a "WYSIWYG form" I mean a layout similar to the print preview layout, which currently allows placement of a letter size form image, with data entry fields layered on top of the image. Essentially, the "WYSIWYG form" could be exactly like the current print view, except users could enter/edit data in the fields. The ability to control tab order would also be nice. I am not asking for the ability to add line and box elements, pasting in an image of the form in the background works fine as it is.