The PDF to ODT converter frees your document from viewer mode, so you can open it with programs like, for example, OpenOffice (although .odt is compatible with many more programs, since it belongs to the OpenDocument standard —in fact, that’s where its acronym comes from: Open Document Format—)
By converting PDF to ODT, editing a .pdf becomes a much simpler task for anyone who wants to modify their document without the need to have a license for Office programs such as Word itself. If you need to, you can also convert ODT to PDF.