|PrimoPDF, like many other free PDF converters, installs as a printer and creates a PDF file when you "print" to it from another application.|
These utilities do not allow for editing of the PDF file.
In most cases, what you need to is scan the document into a word processing application, such as MS Word, edit it and then print it to a PDF converter - assuming PDF is the final format you are going for.
In addition, your scanner software needs to have OCR (Optical Character Recognition) capabilities in order to create a file that can be edited.
If your scanner/scanner software is only capable of creating images from a scanned document, you won't be able to edit any text in the scanned file.
It is my understanding that there are free PDF creation utilities that allow for editing of the document, but I am not familiar with any of them so I can't make a recommendation. (Maybe somebody else will step up.) I just noticed that the PrimoPDF site offers a free trial of utility called nitroPDF, but it's $99 to purchase it.
My main point here is that utilities such as PrimoPDF, CutePDF and PDFcamp Printer are not going to allow you edit the PDF's that they create.