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Highlighting is for marking up a document you are reviewing — deadlines in a contract, figures in a report. Doclium adds real PDF highlight annotations, so they show up in Acrobat, Preview and every other reader, not just here.

How to highlight text in a PDF

1Upload the PDF you want to mark up.
2Enter the words or phrases to highlight and pick a colour.
3Download the highlighted document.

Questions people ask

Which colours can I use?

Yellow, green, blue, pink, orange or purple.

Will the highlights show in other PDF readers?

Yes. They are standard PDF annotations, not an image drawn over the page.

Does highlighting change the text?

No. The text underneath is untouched, so the document stays searchable.

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Everything you can do, in one place

Compress PDF Shrink file size, with the real before/after shown Watermark PDF Stamp CONFIDENTIAL or your own text on every page Header & Footer Running header or footer with auto page numbers Resize to A4 One paper size for every page, scaled not stretched PDF to Markdown Clean .md with headings, lists and tables PDF to Word Layout-aware .docx with text, tables and images Merge PDF Combine documents into one, in the order you pick Split PDF Pull a page range out into its own document PDF to Image Every page as JPG or PNG, zipped for multi-page Chat with PDF Ask questions, every answer cites its source page Summarize Key points from a long document, with citations Translate Any language, side-by-side or replacing the original Highlight PDF Mark up text in six colours, readable in any PDF app Edit PDF Text Find and replace words, keeping size and colour Redact PDF Delete sensitive text for good, not cover it up Protect PDF Lock a document with AES-256 encryption OCR PDF Recover text from a scan so you can search it Rotate PDF Turn sideways pages the right way up, permanently Delete PDF Pages Drop blank or unwanted pages from a document Add Page Numbers Stamp numbers that survive printing

Free to use No account, no signup, no payment.

Encrypted in transit Your library is private to your device. Privacy policy.

Answers you can check Every AI answer cites the page it came from.

Works everywhere Install it as an app on phone or desktop.

The PDF toolkit that reads your documents too

Doclium is a free web app for working with PDFs: merge, split, compress, rotate, protect and convert them in your browser, with no install and no signup to start. Where most PDF tools stop at the file, Doclium also reads it — ask a question and get an answer that cites the page it came from, so you can check it.

Chat with a PDF, summarise a long report, or translate one into another language. Clean documents up with OCR, redaction, watermarks, headers and footers, page numbers and A4 or Letter resizing. Every change can be undone, and every export is previewed before it downloads.

Private by default Your library is yours alone. Documents are scoped to your account or device and are never readable by another user.

HTTPS everywhere All traffic is encrypted in transit with TLS. Your files are not used to train AI models.

Answers with citations The assistant quotes the passage and page behind each answer, so nothing has to be taken on trust.

Free to use The tools are free, with no watermark added to your output and no account needed to begin.

Open a document to read it here. Ask a question and the cited pages are highlighted.

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