How to highlight text in a PDF on every page at once

How to highlight a word or phrase on every page of the PDF

To highlight a PDF, upload the file, type the word or phrase in the "Text to highlight" field, pick a color (yellow, green or pink) and click "Highlight and download". The tool searches every page, paints each match like a highlighter pen and downloads the PDF right away, telling you how many matches it marked. Everything happens in your browser.

What the tool does (and what it doesn't)

• Searches for one exact word or phrase, at least 2 letters long. Below that, the button stays disabled. A phrase that breaks across two lines is found as well; the mark comes out in two pieces, one per line.
• Ignores case and accents: "sao paulo" finds "São Paulo" and "SÃO PAULO".
• Three highlight colors: "Yellow" (default), "Green" and "Pink". The mark is semi-transparent, like a real highlighter: the text underneath stays readable. The mark is drawn onto the page, not added as an annotation: it can't be removed later in a PDF reader. Keep the original.
• One term at a time. There's no list of terms and no categories like "deadlines" or "amounts": only the text you typed.
• No on-screen preview: the click generates and downloads the file right away. What you see afterward is the count, as "N matches highlighted".
• Several PDFs at once: the same term is searched in all of them, each file downloads separately and the count adds everything up. If one of the files doesn't contain the term, the not-found message appears and the pass stops there: the remaining files aren't processed.

When highlighting really helps

• Studying handouts and articles, marking a concept that repeats so you can review it later.
• Reviewing a contract, highlighting one term that needs attention: "penalty", "termination", the name of one of the parties.
• Preparing for a meeting, keeping the points you want to raise in plain sight.
• Finding a term that repeats, such as a name or a case number, without searching page by page.

Step by step to highlight the PDF

1. Open the highlight text tool and upload the PDF (or several).
2. Type the word or phrase in the "Text to highlight" field (it shows the example "e.g. confidential"): at least two letters.
3. In the color selector, choose "Yellow", "Green" or "Pink".
4. Click "Highlight and download". The PDF downloads right away, named after the original plus "-destacado", and the screen shows how many matches were marked.

Since the highlight goes on top of the text, the original content stays readable and the starting file remains on your device. If you marked too much, redo it with a more specific term from the original PDF. The count shown at the end is your check: if you expected ten matches and got three, check the spelling of the term. If, besides highlighting, you want the whole text in an editor, see how to copy all the text from a PDF at once.

How to mark more than one term, in different colors

The search handles one piece of text at a time. To mark two or more terms in the same document, download the result, upload that already-highlighted file again and repeat with the next term, in another color if you like. That way, in a contract, the deadline can be yellow and the amount green, in separate rounds.

Common errors: "we could not find that text"

The message "We could not find that text in the document. Check the spelling or try a shorter piece." has two frequent causes. The first is spelling: a long phrase with a comma or a space that differs from the original won't match; try a shorter piece. The second is a scanned PDF: if the document is a photo or a scan with no text underneath, there's nothing to search, and no match is found. To find out whether your PDF has real text, the PDF details tool shows a "Selectable text" field. To read the text of a scanned document, see how to extract text from a scanned PDF with OCR. What else that inspector shows is in how to view a file's metadata.

Tips for highlighting that helps you study

• Prefer specific terms: searching a very common word highlights the whole text and loses its usefulness.
• Highlight the essentials, not everything: when almost everything is marked, nothing really stands out.
• Use the colors as a code: yellow for what to study, green for what you already understand, pink for what to ask about.
• Download and reread with the highlights: they work as a map of the points you want to return to.

All of the highlighting happens inside your browser: the PDF is handled on your own device and is never uploaded to any server, which helps when you're marking a contract or a confidential document.