Highlight, underline, strike out, leave notes, draw freehand, box and circle things — in a browser tab, on your desktop, or straight from the Chrome extension. Free, no account, nothing uploaded.
Highlight, underline and strikeout mark text you have selected. Sticky notes put a note on the page where you place it — a box you type into, sitting on the page for the reader to see. Freehand drawing lays down an ink stroke wherever you drag, smoothed as it is recorded, so a shaky line comes out as a curve rather than a tremor.
Then the shapes. A rectangle, outline or filled. An ellipse, inscribed in the box you drag, which is how you circle one figure in a table without fighting the geometry. An eraser takes back any markup you added. A comments panel gathers all of it in one list. Flatten bakes it into the page.
Marking up is usually one step in a longer job. When something has to come out of the document rather than be drawn over, redact it so the text is removed and not merely covered. When the pages themselves are the problem, reorder, rotate and delete pages first, then annotate what is left.
A highlighter is only worth anything if the colour lands on the words. Highlight, underline and strikeout here work over a real text selection: you drag across the sentence the way you would in a browser, and the mark is attached to the characters you picked.
That includes line wraps. A clause that starts three quarters of the way along one line and finishes in the middle of the next gets two pieces of highlight, each shaped to the text it covers, instead of one rectangle stretched across both. Underline and strikeout behave the same way, which is why a struck-out sentence reads as a struck-out sentence rather than a line ruled through a paragraph.
Plenty of PDF tools only offer a translucent box you place by eye. It looks close enough until you zoom in, or until the highlight clips the descenders on one line and the ascenders on the one above.
Annotations in a PDF are separate objects sitting above the page. That is what makes them easy to change — and it is also what lets whoever opens the file next drag your note somewhere else or delete it outright. Flattening writes them into the page content instead. Afterwards there is nothing left to select: the marks are part of the page.
It is a real implementation of the appearance-placement algorithm in PDF 32000-1 §12.5.5 — the arithmetic that maps an annotation's appearance onto the rectangle it belongs in — and the tests render the output through PDFium to check that the marks land where they were.
Flatten deliberately leaves some things alone: links, popups, annotations marked Hidden or NoView, and anything that has no appearance stream of its own. A flattened link would stop being a link, a hidden annotation would become visible, and an annotation with no appearance has nothing to draw. So they are skipped rather than mangled, and they stay in the file as annotations after everything else has been baked in. Worth knowing if you flatten a form or a document full of cross-references.
Every marked-up item in the document shows up in the comments panel, in one place. On a forty-page contract that is the difference between remembering where you left a note and scrolling until you find it.
It is a flat list you read. There are no replies, no threads, no mentions, and no second person marking up the same file alongside you. If your review needs a back-and-forth, that happens wherever your team already talks; this panel's job is to show you what is on the document.
Search for a way to annotate a PDF and most of what comes back wants the file first. Think about what that means for the documents people actually mark up. To put a note in the margin of a contract, you would begin by handing the contract to somebody else's server — a draft nobody outside the deal was meant to read, sent to a company you know nothing about, for a job that never needed to leave your desk.
Nothing here is uploaded, because there is nowhere for it to go. The web app does the work in the page itself. The Chrome extension declares no permissions and no host permissions at all, so the browser would not let it reach a server even if something in it tried.
Annotating is free in all three builds — the desktop app for macOS and Windows, the web app in a browser tab, and the Chrome extension — with no account and no page limit. The only two tools in the whole product that cost anything are the watermark tool and OCR.
In a browser tab, with nothing to install and nothing to sign up for.
No. Highlights, notes, ink strokes and shapes are saved as standard PDF annotation objects, so any ordinary PDF viewer draws them — the one built into a browser, the one on a phone, whatever they already open PDFs with. If you would rather they could not move or delete anything, flatten the file before you send it.
Flattening writes the markup into the page itself, so it is no longer a separate object someone can drag around or remove. Use it when the annotated file is the record you are handing over. Keep an unflattened copy if you might still want to change something, because the marks cannot be lifted back out of a flattened file.
Yes. The eraser removes markup you put on the document — a highlight, a note, an ink stroke, a shape. It works on the annotations, not on the page beneath them, so it will not rub out the document's own text or images. Once a page has been flattened the marks are part of the page and the eraser no longer reaches them.