AbleWord (tinyurl.com/h2urup8) is the only free PDF editor we’re aware of that will import a PDF and make it completely editable. It’s best when importing PDF files that were created in Word, but will attempt to replicate all PDF files. The end result won’t look identical to the original, but will be close. Foxit Reader (foxitsoftware.com) is a lightweight alternative to Adobe Reader and many people prefer it. It’s more than just a PDF reader though, and it has a wide range of powerful tools. You can’t edit the contents, but text can be struck through with a line and replaced by a pop-up note. You can also insert sticky notes, attach files to pages, click anywhere and add text, add text boxes and callouts, draw with a pencil, add rectangles, lines, arrows, polygons and clouds, and add stamps like Approved, Rejected, Draft, and so on. It’s great if you have to comment and annotate PDFs. PDF-XChange Viewer (tracker-software.com) offers an almost identical set of features to Foxit Reader and it is useful for annotating PDFs in a similar manner. PDFCool Free Studio is buggy and can quit with an error message, but when it works, it has some useful features. For example, it can extract the text and images from a PDF and this would enable you to edit them elsewhere, such as in a Word document. Text can be typed onto the page and there are some basic drawing functions like lines, circles and rectangles. It’s not as good as Foxit Reader, though.
LibreOffice (libreoffice.org), pictured, the free Office alternative, is worth considering if you want to edit the text in a PDF file. It loads PDFs and it can cope with very large documents with hundreds of pages. The only snag is that each line of text is a text box, which makes it awkward to edit text large amounts of text.