1. An apparatus for editing a document, the apparatus being installed on a first terminal, that is, a mobile terminal of a user, in order to edit a document of a document file stored in the first terminal, the apparatus comprising: a document storage unit configured to store at least one document file; and an edited document generation unit configured to extract an area of interest from a document file stored in the document storage unit and displayed on a display unit of the first terminal, and to generate an edited document; wherein the document file is a portable document format (PDF) file.