To remove highlight from PDF documents, open the file in OpenPdfEdit, switch to Annotate and choose Remove markup. Highlights, sticky notes, ink and stamps come off in one step, on your own machine. Free, with nothing uploaded and no account.
Open the document in a browser tab, in the desktop app for macOS and Windows, or through the browser extension. Switch to Annotate at the top of the window and choose Remove markup. That is the whole job: it goes through every page of the document and takes off every highlight, note, ink stroke and stamp, together with the popup windows that belong to them. Then save.
It is an ordinary edit, so it can be undone. If more came off than you meant, undo it and take the marks off one at a time instead: pick the Select tool, click the highlight you want gone, and delete it. That is the better way to remove highlight from PDF pages when the rest of the markup should stay.
Most of the time a highlight is an annotation: a separate object listed with the page, which is why a reader lets you click it. Removing those is simple bookkeeping, and any editor can do it.
The harder case is markup that arrives already flattened. Tablet note-taking apps, scanner apps and “print to PDF” from a marker tool tend to write the pen strokes as one transparent image laid over the whole page, with no annotations at all. Open one of those and there is nothing to click; the marks look as much a part of the page as the text under them. This is the version people usually cannot get rid of, so when you remove highlight from PDF files here, that layer is taken off too.
Dropping the wrong image would empty a page, so the test is narrow. An image counts as a markup layer only if it has its own transparency, covers at least 90% of the page, and the page also draws something else. A scan saved as a transparent image, alone on its page, is the page itself, and it stays.
A highlighter that went across paper before the paper was scanned is part of the picture. The yellow is in the same pixels as the words, and nothing that tells markup from document can separate the two. If you need to remove highlight from PDF scans of a marked-up printout, the honest answer is that this tool will not do it, and it does not pretend to.
Pen strokes drawn as ordinary vector paths are the other gap: on the page they look exactly like a diagram, so they are left alone rather than guessed at. Links and form fields also stay. They are stored next to the highlights, but nobody drew them, and removing them would break navigation or destroy the form.
Like every ordinary edit in this app, the result is saved as a new revision added to the end of the file. That is what makes it undoable, and it is the right trade for tidying a document. It also means the earlier revision, markup included, is still in the bytes.
When the notes are the sensitive part and the file is going to someone else, use redaction instead: it rewrites the whole file, so nothing survives in an earlier revision. And if you want the opposite of all this, so that nobody can remove your highlights, flatten the PDF.
Remove markup is free in all three versions, with no sign-in and no page limit. It is not one of the paid tools. Nothing is uploaded: the web app does the work in the page itself, and the desktop app works offline.
OpenPdfEdit is an open source PDF editor, so the code that decides what counts as markup is public. You can read exactly which rules a page has to meet before anything is taken off it.
Open the file, switch to Annotate, choose Remove markup, save. Nothing to install, nothing to sign up for.
Guides: How to flatten a PDF · Two ways to save a PDF · All guides
No. Marker ink that was on the paper before it was scanned is part of the image, in the same pixels as the text, so it cannot be separated from the page. Remove markup takes off annotations and transparent pen layers that an app placed over the page, not marks inside a scan.
Yes. Remove markup clears the whole document in one step, so for a single highlight use the Select tool instead: click it and delete it. Either way the change can be undone.
No. Links and form fields are stored alongside highlights, but they are not something a person drew, so they are kept. Removing them would break navigation or the form.