How to highlight text in a PDF

Highlight text in a PDF with Quick PDF

1. Open the PDF in Quick PDF Go to quickpdfapp.com in your browser, sign in, and choose your PDF from Files, Downloads or your desktop. The file opens on your own device; it is not uploaded to a server.
2. Choose Highlight in the toolbar Tap or click Highlight in the editor toolbar. Pick a colour first so every mark you make uses it.
3. Drag over the text Drag across the words you want to mark, or tap a line to highlight it in one go. Zoom in on a phone so you can start and stop exactly where you want.
4. Fix mistakes with Undo If a highlight lands in the wrong place, tap Undo and try again. Redo brings it back if you undo one step too many.
5. Add notes if needed Use Comment to pin a sticky note next to a highlight, or Draw to circle something by hand.
6. Download or Share the highlighted PDF Tap Download to save the new copy, or Share to send it straight to Mail, Messages or a cloud folder. The highlights are part of the saved file.

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Highlighting a PDF on iPhone, Android, Mac and Windows

The steps above are the same on every device because Quick PDF runs in the browser. The only real difference is where your file lives:

• iPhone and iPad: in Safari, the file picker opens the Files app, which includes Downloads, On My iPhone and iCloud Drive. Mail attachments need to be saved to Files first (tap the attachment, then the share icon, then Save to Files).
• Android: in Chrome, the picker shows Downloads and recent files. Files from Gmail or WhatsApp usually end up in Downloads once you open or save them.
• Mac: drag the file from Finder or pick it from Downloads in Safari or Chrome.
• Windows: choose it from Downloads or Documents in Edge or Chrome.

On a phone, highlighting with a finger is easier when you zoom in two or three steps. A stylus on an iPad or a Samsung tablet gives the most precise marks.

How to use highlight colours so your notes stay readable

Quick PDF offers several highlight colours. A simple colour system makes a long document far easier to come back to:

• Yellow for key facts you want to find again.
• Green for things you agree with or have checked.
• Pink or red for problems, questions or anything that needs a reply.

If you are sending the file to someone, tell them what your colours mean in one line of your email. For anything longer than a word or two of explanation, add a sticky note with Comment instead of trying to say it with colour alone. Our guide to adding comments to a PDF covers that.

Other ways to highlight a PDF

You may already have a highlighter built into your device. Here is how they compare:

• Mac Preview has a highlight button in the Markup toolbar and works well on text-based PDFs on a Mac.
• Microsoft Edge on Windows can highlight text in PDFs it opens, which is handy for a quick read-through.
• iPhone Markup (in Files or Mail) gives you a highlighter pen, but it is a freehand marker, so lines can come out wobbly.

Quick PDF is the better fit when you want the same tool on your phone and your computer, when you also need to draw arrows or boxes, add sticky notes, sign or fill in the same document, or when you would rather the file never leave your device.

Why won’t my PDF let me highlight text?

These are the most common reasons a highlighter will not behave:

• The PDF is a scan or a photo. The words are part of an image, so there is no real text for the tool to snap to. Drag across the area instead of tapping a line, or draw a box around it with Shapes.
• The PDF is password-protected. If it asks for a password to open, you need that password. Our Unlock tool can remove a password you know.
• You are still in another tool. If Draw or Add text is active, your drag does something else. Tap Highlight again before dragging.
• The highlight covers the words. Pick a lighter colour so the text underneath stays easy to read.

Will my highlights show up for other people?

Yes. When you tap Download or Share, the highlights are saved into the PDF itself, so they appear in Acrobat, Preview, Chrome, Edge and phone viewers. A good habit is to open the downloaded copy once before sending it, just to check everything looks right.

Keep the original file as well. Highlights are hard to remove once someone else has the file, so if you need a clean copy later, start again from the original. If the highlighted file is too large to attach, see what to do when a PDF is too large to email.

Questions people ask