# PDF Comment Markup Draw review-style side comments, arrows, and highlight regions on PDF pages > Canonical page: https://elysiatools.com/en/tools/pdf-comment-markup - **Category:** Document Tools - **Keywords:** pdf, comment, markup, review, highlight, annotation ## Overview Apply markup overlays to an existing PDF. **Includes:** - Highlight boxes for review focus - Side comment boxes with connector arrows - Left/right note placement for editorial workflows ## Inputs - **Input PDF** (file): Upload review draft PDF - **Markups JSON** (textarea): \[ { "page": 1, "kind": "highlight", "x": 15, "y": 22, "w": 40, "h": 8, "text": "Risk claim needs evidence" }, { "page": 1, "kind": "comment", "x": 18, "y": 40, "w": 36, "h": 10, "text": "Please simplify this paragraph.", "side": "right" }, { "page": 1, "kind": "comment", "x": 20, "y": 58, "w": 30, "h": 9, "text": "Add references to appendix.", "side": "left" } \] - **Highlight Opacity** (number) - **Note Box Opacity** (number) - **Note Width Ratio** (number) ## When to use - When you need to provide structured feedback on draft documents for colleagues or clients. - When you want to highlight specific sections of a PDF while keeping the main text clean. - When you need to organize editorial notes on either the left or right margins of a page. ## How it works - Upload your target PDF document using the file input. - Define your annotations in the Markups JSON field, specifying the page, markup type, coordinates, and text content. - Adjust the opacity and width settings to ensure your comments are legible and visually aligned. - Process the file to generate a new PDF with your review annotations permanently applied. ## Use cases - Academic peer review for marking up research papers with specific evidence requests. - Corporate document editing for providing clear, side-aligned feedback on policy drafts. - Legal contract review for highlighting clauses that require further clarification or revision. ## Frequently asked questions ### Can I place comments on both sides of the page? Yes, you can specify 'left' or 'right' in the side property within your JSON configuration for each comment. ### What file formats are supported? This tool exclusively supports PDF files for both input and output. ### How do I control the transparency of the highlights? Use the Highlight Opacity slider to adjust the visibility of your highlighted regions between 0.08 and 0.6. ### Is the markup permanent? Yes, the tool generates a new PDF file with the annotations flattened into the document. ### What happens if my JSON syntax is incorrect? The tool requires valid JSON format; ensure all brackets and quotes are properly closed to avoid processing errors. ## Related tools - [2026 PDF Calendar Designer](https://elysiatools.com/en/tools/pdf-2026-calendar-designer): Design and export stylish 2026 printable PDF calendars with bimonthly, quarterly, semiannual, or annual single-page layouts - [PDF Form Fill Batch](https://elysiatools.com/en/tools/pdf-form-fill-batch): Fill one PDF form template with an array of records and output one filled PDF per record (ZIP) or a merged PDF - [Fitness Workout PDF Generator](https://elysiatools.com/en/tools/fitness-workout-pdf-generator): Generate a printable workout-plan PDF from JSON or CSV data with exercise tables, progress boxes, and optional QR video links - [LibreOffice Template Fill Merge](https://elysiatools.com/en/tools/libreoffice-template-fill-merge): Replace placeholders in DOCX template and render merged records to PDF using LibreOffice - [PDF Annotation Export](https://elysiatools.com/en/tools/pdf-annotation-export): Extract existing annotations (highlights, comments, stamps, links, markup) from a PDF into JSON - [PDF Page Range Extractor](https://elysiatools.com/en/tools/pdf-page-range-extractor): Extract only selected PDF pages with OpenDataLoader and export the subset as Markdown, JSON, or text - [OCR PDF to Structured JSON Bridge](https://elysiatools.com/en/tools/ocr-pdf-to-structured-json-bridge): Extract the PDF text layer with geometry (lines by y-position, tables by column gaps, headings by font size, colon key-value pairs), then fill a user-supplied JSON Schema field by field — labels matched by normalized keys, values coerced to declared types and validated with ajv. - [PDF Code Snippet Viewer](https://elysiatools.com/en/tools/pdf-code-snippet-viewer): Render code snippets with mono font, background boxes, and clickable Git repository links ## Samples - [PDF Samples](https://elysiatools.com/en/samples/pdf-samples): Generated PDF samples from tools dated 2026-02-01 to 2026-02-10 - [Markdown Slide Deck Samples](https://elysiatools.com/en/samples/md-slide-deck-to-pdf): Remark/Marp style Markdown slide decks for testing PDF export layouts - [Terraform Plan JSON Samples](https://elysiatools.com/en/samples/terraform-plan-json-samples): Sample Terraform plan JSON files exported from terraform show -json style payloads for dependency visualization and change review - [Distributed Tracing Samples](https://elysiatools.com/en/samples/distributed-tracing-samples): Comprehensive distributed tracing examples using Jaeger, OpenTelemetry, and other modern observability tools for microservices architecture ## Related content - [PDF Forms, Navigation, and Review Workflows](https://elysiatools.com/en/hubs/pdf-forms-navigation-review-workflows): Prepare fillable PDF forms, add internal navigation, mark review issues, style delivery pages, and verify signatures before handoff.