Best Free PDF Annotators

Apryse (formerly PDFTron) powers the future of document technology. We help businesses, developers, and enterprises handle documents with unmatched speed, accuracy, and security. Whether running in secure server environments or delivering seamless web-based experiences, Apryse makes document workflows smarter and easier. With Apryse, you can: Embed powerful document features directly into your apps — from viewing and editing to collaboration and compliance. Run at enterprise scale on secure server infrastructure, ensuring reliability without cloud dependencies. Deliver seamless in-browser document experiences with responsive, accessible, and feature-rich web capabilities. Trusted globally, Apryse empowers organizations to simplify operations, enhance productivity, and create exceptional document experiences.

Drawboard PDF is the most intuitive PDF editing and markup app for Windows, iOS, macOS, android and web. Powerful PDF tools that feel good to use. Drawboard PDF – Get all the essential free. Mark up and edit any PDF with the ease of pen and paper. Drawboard Pro toolset - Upgrade to use advanced tools and Store+Share with your team. MARK UP AND DRAW All the drawing tools you need to mark and collaborate with the feel of pen and paper. INSERT Insert elements into your documents like, text, notes, callouts, signatures, images, audio notes, and more. MEASURE Take accurate measurements of elements on-page with technical measurement tools and calibration. MANAGE Local and Clouds PDFs in one place. Merge, split, reorder and compress COLLABORATE Real-time collaboration on-page in real time with instant syncing CROSS-PLATFORM Work from anywhere on any device, in real-time!

Adobe PDF Library is the only commercial PDF SDK built on Adobe Acrobat's own core engine, delivering the same rendering accuracy, PDF spec coverage, and behavior as Acrobat itself. Available in Modern C++, Adobe C/C++, .NET, .NET Framework, and Java, and supported on Windows, macOS, and Linux. Create, edit, merge, split, annotate, and watermark PDFs programmatically; convert to and from Word, Excel, PowerPoint, PDF/A, PDF/X, and more; add OCR, digital signatures, redaction, and encryption; and process AcroForms and XFA forms. SOC 2 Type 2 compliant, with a 91% customer retention rate among enterprise users. For enterprise deployment, the pdfRest API Toolkit Container packages this technology as a self hosted REST API for on premises, private cloud, or hybrid environments. Datalogics also offers Scout, an AI assistant, and an MCP server so teams can bring PDF capabilities into AI powered workflows.

CoolNew PDF offers all-in-one experience to awesomize your PDF experience. All the tools you’ll need to be more productive and work smarter with documents.21 tools to convert, compress, and edit PDFs . Conversion features include CAD, office, image, texted and scanned copy conversions. Editing features include text, image, eraser, page number, size, watermark, paragraph and more. Users can combine or split PDFS, extract contents and optimize pdfs. merge and compress PDF. Reading and annotation features included. It edits, annotates, converts and combines file by one click, makes your tasks finish faster. CoolNew PDF offers you a familiar experience for editing PDF, just like you did it in Office.