For maximum privacy and control, you need to self-host any available open-source PDF editors on your own server.

Consider PDF Reader Options Before you open a PDF file, know that you have both native and alternative PDF reader applications to choose from. Here are a few popular choices to consider: ...

You can easily open a .doc file on the internet, in Microsoft Word, on Google Docs, or in Libre Office and make the edits you need. However, PDF documents are a little bit more difficult to edit.

Dropbox already has many integrations for files stored on it, including Microsoft’s Office Online and Salesforce. More than 18 billion PDF files are stored on Dropbox, Perera wrote.

Press "Alt-F2" to open a command line prompt within Unity. Type the command for Evince with your PDF file's name, file extension and its full path relative to the Home directory.