Open any PDF, highlight passages, add comments, and download a clean annotated file — with no watermarks, no Adobe install, and no signup required to try the basic tools. Works on scanned documents, flat PDFs, and interactive forms.
Drop your PDF here to start annotating
or click to browse — your file stays in your browser
The annotator above gives you free highlight and text-comment tools in the browser. Inside the full editor you also get drawings, shapes, signatures, stamps, and reusable templates.
Drag yellow, green, blue, or pink highlight boxes over any part of the PDF. Works on scanned and flat PDFs alike — no underlying text layer required.
Click anywhere to drop a text note, label, or comment. Useful for review feedback, sticky-note style remarks, or filling in blank lines.
Inside the full editor, draw text fields anywhere on the page to make a flat or scanned PDF interactively fillable.
Drop in a saved signature, stamp, logo, or any image. Resize and reposition until it sits exactly where you want it.
Outline answers, mark sections, or hide content with colored rectangles. Tweak fill, opacity, and color per shape.
Mark up contracts and revisions with strikethroughs and underlines. Perfect for redline reviews or showing what changed.
Save common annotations — review remarks, approval stamps, instructions — as templates and reuse them across documents.
Every annotation is editable. Move, resize, recolor, or delete anything you added. Full undo and redo, no lock-in.
Download a clean PDF with annotations baked into the page. Opens correctly in Preview, Acrobat, browsers, and on mobile.
PDF annotation is for review marks: highlights, notes, and text comments. If you need to complete a form or reorganize pages, use the related JustFill tools below.
From a fresh PDF to a marked-up download in under two minutes — no signup, no installs, no Adobe required.
Drag and drop a PDF onto the annotator above, or click to browse. The file is read locally in your browser — nothing is uploaded for the basic annotation tool.
Choose Highlight to mark passages with colored boxes, or Text to drop a note, label, or comment anywhere on the page.
Click and drag to draw a highlight box over the passage you want to mark. For comments, click where you want the note and type your text.
Use the page controls to move between pages. Annotations are tied to the page they were drawn on, so a note on page 3 stays on page 3.
Use Undo to remove the last annotation on the current page. You can keep adjusting until everything looks the way you want.
Click Save PDF. Your annotations are baked permanently into the document and you get a clean file you can email, print, or archive.
Most free online PDF annotators add watermarks, force a signup before download, cap file size, or only work with PDFs that already have a text layer. JustFill removes those compromises.
Comparison reflects typical free online PDF annotation tools as of 2026. Specific features and limits vary by provider — check each tool's current terms.
JustFill annotates any PDF you can open — there's no special format required.
Photos and scans of paper forms, contracts, receipts, and notes. JustFill renders them as an image you can mark up — no OCR step needed for highlighting or commenting.
PDFs exported from Word, Pages, Excel, Google Docs, or design tools. They look like documents but have no interactive layer. JustFill annotates them as easily as native PDFs.
PDFs with built-in form fields. The annotator overlays highlights and comments on top, so you can review and mark up an interactive form without breaking its native fields.
PDFs that are essentially a wrapper around an image (common with photographed contracts or older scans). Annotation works because JustFill marks the rendered page, not an underlying text layer.
Annotate long documents — research papers, ebooks, reports, manuals. Page-by-page navigation keeps your annotations organised across hundreds of pages.
Highlight and text annotation runs locally in your browser. Your file never leaves your device — useful for legal contracts, medical records, or anything covered by confidentiality.
JustFill's annotator is built for the people who actually mark up PDFs every day.
Highlight key passages in textbooks, papers, and lecture notes. Add margin comments while you study, then export a personal study copy with everything marked up.
Review contracts and case files in the browser without uploading sensitive material. Highlight clauses, add review comments, and produce a marked-up copy for your team.
Give visual feedback on PDFs of mockups, brand decks, and proofs. Highlight problem areas and drop concise comments — clearer than email threads, faster than design tools.
Annotate research papers and source material. Mark quotes, add citation notes, and keep annotated reading lists you can search and revisit later.
Mark student submissions with highlights and inline comments. Export a clean PDF to send back — works for assignments, essays, lab reports, and worksheets.
Run editorial reviews on PDFs of articles, manuscripts, and proposals. Add inline comments and highlight changes without losing the original layout.
Highlight and text-comment annotation runs entirely on your device — no uploads to a third-party server. The PDF you annotate and the file you download never leave your browser. That's a real difference for confidential contracts, medical forms, and any document covered by a non-disclosure agreement.
The PDF annotator is responsive and runs in any modern browser — Chrome, Firefox, Safari, Edge — on Windows, macOS, Linux, ChromeOS, iPadOS, Android, and iOS. Quick highlights from your phone work fine; for dense markup a tablet or laptop gives you more precision.
Beyond highlights and comments, JustFill lets you draw fields, insert signatures, save reusable templates, and auto-detect fields with AI — across scanned, flat, and interactive PDFs. Free to start, no credit card.
GDPR compliant. No watermarks. Cancel anytime.
Everything people ask before using an online PDF annotator.