The best free PDF editor depends on what you mean by "editing." For annotations and form filling, several tools are genuinely free and capable. For changing body text in a PDF, the free options are more limited. Here's what actually works without paying.
For Annotations, Signing, and Form Filling: Multiple Good Free Options
Adobe Reader (free) covers annotations fully โ highlights, sticky notes, strikethrough, freehand drawing, and form field filling. It's the most compatible option since it's from the PDF spec creator, and it works on Windows, Mac, iOS, and Android. The only catch is that it's Adobe software, which some people prefer to avoid.
Preview on Mac is built-in and free. It handles highlighting, text annotations, signatures, form filling, and freehand markup well. For Mac users, it covers the majority of everyday annotation needs without installing anything.
Microsoft Edge (built into Windows 10/11) handles highlighting, text notes, and drawing directly in the browser. No installation needed for Windows users.
For Browser-Based Editing Without Installation: WukongPDF
WukongPDF's PDF Editor runs entirely in the browser โ no download, no account required for basic use. It supports adding text, highlighting, annotations, signatures, and basic editing operations. Because it runs in any browser, it works on any device: Windows, Mac, Chromebook, iPhone, Android.
For most people who need to occasionally add text, sign a document, or annotate something, a browser-based tool like this is the most practical free option โ no installation, accessible from any device, and it handles the most common tasks cleanly.
For Changing Body Text: Free Options Are Limited
If you need to change existing text in a PDF body โ fix a typo, update a number, rewrite a sentence โ truly free tools with this capability are rare. LibreOffice Draw can open PDFs and edit individual text elements, but it's not a dedicated PDF editor and complex layouts break badly. Inkscape can edit PDFs as vector graphics, which works for simple one-page documents.
For text editing, the more practical free approach is often: convert the PDF to Word (Google Docs or a converter tool), make your edits, export back to PDF. This preserves full text editability without needing dedicated PDF editing software.
PDF-XChange Editor: The Best Free Tier With Real Editing
PDF-XChange Editor (Windows only) has a free tier that's genuinely capable. The free version supports annotations, form filling, text editing with some limitations, basic page management, and OCR. It adds a watermark on pages you edit in free mode for certain operations โ but for annotation and form work, no watermark appears. It's the closest to a free full desktop PDF editor that exists on Windows.
The Honest Bottom Line
For annotations, signing, and form filling: Adobe Reader, Preview (Mac), Edge (Windows), or any browser-based tool โ all free, all capable. For body text editing: no single free tool does this well. The convert-to-Word workaround covers most cases. For anyone who edits PDFs frequently enough to feel the limits of free tools, a paid option starts to make sense โ but most people's needs are fully covered without spending anything.