Annotate PDF Online
Annotate PDF documents with highlights, comments, underlines, and drawings. Perfect for document review and collaboration.
Annotate PDF is a free browser-based tool from SublimePDF. No registration, no file uploads, no watermarks — your files stay on your device throughout the entire process.
Drop your PDF files here
or click to browse — up to 50MB
Key Annotate PDF Features
How to Annotate PDF Online
Follow these simple steps to annotate pdf your files in seconds.
Upload your PDF
Select the PDF document you want to annotate.
Add annotations
Use the toolbar to highlight text, add comments, draw, or insert shapes. Choose from multiple colors and styles.
Save and share
Download your annotated PDF to share with colleagues or save for reference.
About the Annotate PDF Tool
SublimePDF's Annotate PDF tool is perfect for reviewing documents, studying materials, or providing feedback. Mark up your PDFs with colorful highlights, detailed comments, precise underlines, and freehand drawings. Add sticky notes with your thoughts, draw arrows to call attention to specific sections, and organize your annotations by color for easy categorization. Whether you're a student, a professional reviewer, or a team lead, our annotation tools make document collaboration effortless.
Why Use Annotate PDF Online?
SublimePDF's annotation engine adds highlights, comments, underlines, and freehand drawings as standards-compliant PDF annotation objects — not flattened pixels. Your annotations remain selectable and removable in any PDF reader, making collaborative review workflows seamless across teams using different software.
- Completely free — no registration, no watermarks, no hidden fees.
- Private by design — files stay on your device; nothing is uploaded.
- Instant results — browser-based processing means no waiting for server queues.
- Works everywhere — Chrome, Firefox, Safari, and Edge on desktop, tablet, or mobile.
Privacy & Security
Your privacy matters. When you use SublimePDF's Annotate PDF tool, all processing happens directly in your web browser using WebAssembly technology. Your files are never uploaded to our servers, never stored, and never seen by anyone but you.
About the PDF Format
PDF (Portable Document Format) was developed by Adobe and standardized as ISO 32000. It preserves document formatting across all devices and platforms, making it the universal standard for sharing and archiving documents.