Scanned documents are only photo images with no editable text.
In order to extract the text out of scanned documents, please process the image with optical character recognising function – known as OCR
This will create text layer which can be edited.
The Professional package of Expert PDF doesn’t include OCR module.
You may order it by pressing on Modules and Packages tab in Expert PDF software and press on Module OCR.
Order it and enter the new activation code to unlock it.
Now process the scanned document, edit the text and save changes as new PDF file.