You can use PDF Annotator to edit all documents in Portable Document Format (PDF, see https://en.wikipedia.org/wiki/Pdf).
To edit a PDF document in PDF Annotator, select it using File Open. You can also select a recently opened document from the list that appears under File Open.
You can also bring a file built by another application that supports drag'n'drop (such as Windows Explorer) into PDF Annotator's workspace by dragging it with the mouse and releasing it.
If documents cannot be opened for editing in PDF Annotator due to restrictions imposed by the original author, PDF Annotator will automatically offer to create a Digital Copy when attempting to open the document. When creating a Digital Copy, the document gets printed to a virtual printer provided by PDF Annotator, and a new PDF document will be created. This new document, the Digital Copy, will not be subject to any restrictions.
If PDF Annotator has been defined as the Default PDF Application, you can open a PDF file by double-clicking it in Windows Explorer.
If in Extras Settings Integration Explorer the Add PDF Annotator to Explorer's context menu option is turned on, you can use Windows Explorer to right-click a PDF file, and open it by selecting -> PDF Annotator from the context menu.