If someone sends you a PDF that you’d like to convert into a Word document to edit, you can. Just open it and respond “OK” when it asks you if you to convert the PDF. This will prevent the formatting problems associated with editing or copying and pasting from the PDF.
You can also save a Word file as a PDF (click File > Export > Create PDF/XPS), or save just a portion of a file as a PDF (select a page range). And you can password-protect the PDF, too.