When a user creates a portable document format file, of PDF, he sets the file as interactive or flat, explains Adobe Reader X product support. An interactive file allows others to fill in or modify the form, but a flat file allows no modification.
Although the Adobe Acrobat Reader does not allow editing flat files, other PDF readers, such as Foxit Reader, enable users to edit flat PDF files, notes PCWorld. On Macintosh, the Preview program allows changes to PDF files, according to Macworld. Saving the edited file requires using the Print to PDF option from the Print menu. Starting with Office 2013 and 2016, Microsoft Word can directly open and modify PDF files, reports Microsoft Office Support. The conversion works best with files that are mostly text, but Word imports graphics, too.
Scanned files or images exist in graphics formats that require conversion to an editable PDF document, explains Adobe Acrobat DC tutorials. The Recognize Text option coverts text in a graphic into editable and searchable content. If the image is low quality, an editing option permits manual correction of problems. This feature is available in the purchased Adobe Acrobat DC software, which offers a trial version so users can try the software before purchase.