Annotate PDF

About PDF Annotation Tool

This free online PDF editor turns markup into real, editable objects. Draw text, highlights, underlines, strikethroughs, freehand strokes, rectangles, ellipses, arrows and lines, then select any object to move it, resize it with handles, recolour it, change its opacity or reorder it in the layers panel. Cover mistakes with the whiteout tool, hide sensitive data with a redaction box, drop in a signature or logo image, work in fullscreen, zoom from 25% to 400% and undo or redo every step. All processing happens in your browser - your files are never uploaded to any server.

What annotation tools are available?

You can use: Text (add text anywhere), Highlight (yellow highlighter), Underline, Strikethrough, Freehand Pen (draw freely), Rectangle, Circle/Ellipse, Arrow, and Line. Each tool supports custom colors, sizes, and opacity levels.

Can I edit an annotation after adding it?

Yes - every markup stays a live object. Pick the Select tool (V), click the object on the page or its row in the Layers panel, then drag it to move, pull a handle to resize, or change the colour, line width, opacity, font and fill from the toolbar. Arrow keys nudge by 1 point (10 with Shift), Ctrl+D duplicates and Delete removes.

How do I erase or hide something on the page?

Use the Whiteout tool (E) to drag a white box over the content you want to cover, or the Redact tool (B) for a solid black box over sensitive data. Both are opaque filled rectangles, and you can change the fill colour afterwards to match a coloured background. Because the export flattens them into the page content, the covered area is no longer visible in the final PDF.

How do I draw a perfect square or circle?

Hold Shift while dragging. Rectangles become squares, ellipses become circles, and lines or arrows snap to the nearest 45 degrees. Shift also keeps the aspect ratio when you resize an object from a corner handle.

Can I rotate pages of the PDF?

Yes. The two rotate buttons above the canvas turn the current page 90 degrees left or right, and the third one rotates every page at once. Your markup rotates with the page, so nothing shifts out of place, and the new orientation is written into the exported PDF - handy for scans that came in sideways.

What does the Layers panel do?

It lists every object on the current page, topmost first, exactly like a design app. Click a row to select the object, use the arrows to bring it forward or send it backward, the eye to hide it from the page and the export, the padlock to lock it against accidental edits, and the cross to delete it.

Can I add a signature or logo image?

Yes, three ways: choose the image tool (I) and pick a PNG or JPG, drag an image file straight onto the page, or paste one from the clipboard with Ctrl+V. A transparent PNG signature works best. The image lands where you clicked (centred if you picked the tool from the toolbar), and you can then move it, resize it from any handle and set its opacity like any other object.

Is there a fullscreen mode and zoom?

Yes. The fullscreen button above the canvas expands the whole editor - toolbar, page thumbnails, canvas and layers - to the full screen, and Escape leaves it. Zoom runs from 25% to 400% with the +/- buttons, Ctrl+mouse wheel, or the fit-width button (shortcut 0).

How do I add text to a PDF?

Select the Text tool from the toolbar, click anywhere on the PDF page where you want to add text, type your text in the input box that appears, then click Add to confirm. You can change the font size and color before adding.

Can I highlight text in the PDF?

Yes! Select the Highlight tool, then click and drag over the area you want to highlight. The highlight uses a semi-transparent yellow color by default, but you can change the color and opacity.

How do I draw shapes?

Select Rectangle, Circle, Line, or Arrow from the toolbar. Click and drag on the PDF to draw the shape. You can customize the color, line thickness, and opacity.

Can I undo annotations?

Yes! Click the Undo button to remove the last annotation on the current page. You can also click Clear Page to remove all annotations from the current page, or Clear All to remove all annotations from the entire document.

What is the maximum file size?

The maximum file size is 50MB. For larger files, consider compressing the PDF first.

Is my PDF file secure?

Absolutely! All annotation processing happens locally in your browser. Your PDF file is never uploaded to any server, ensuring complete privacy and security.

Does it work on scanned or rotated PDFs?

Yes. The tool reads each page's rotation flag, so annotations and stamps land in the correct place on pages rotated 90, 180, or 270 degrees - common in scanned, legal, and CAD documents. Note that markup on a scanned image is drawn on top of the image; the underlying scan stays as-is.

Are annotations flattened into the PDF or kept as an editable layer?

Annotations are flattened (burned) directly into the page content using pdf-lib. They become part of the document and cannot be moved or deleted by a later PDF reader, which is what reviewers and document-control teams usually want. Existing content, form fields, and pages you do not touch are preserved.

Can I add Bates numbers or 'Page X of Y' across the whole document?

Yes. Enable Page Stamping, pick Bates (prefix + zero-padded number), 'Page X of Y', or number only, choose a corner and start number, then apply. The stamp loops over every page at export with a consistent sequential identifier - ideal for legal discovery and engineering submittals.

Is text searchable after export, and are existing fields kept?

Text you add and Bates stamps are real PDF text, so they stay selectable and searchable. The tool only adds your markup on top of the original - it does not rasterize or strip the existing page content or form fields.

Can I preview before downloading?

Yes! After applying annotations, you can preview the annotated PDF directly in the browser before downloading. Use the fullscreen button for a larger view.