InstantToolsPro Team
You are reading a PDF and want to mark the important lines: a clause in an agreement, a formula in your notes, or a figure in a report. You do not need a PDF program for that. The free PDF Editor on InstantToolsPro lets you highlight any part of a PDF in your browser, with no app and no signup.
We tested it on a dummy PDF with English text, Hindi text and a table, and then looked inside the downloaded file. This guide covers the steps, the color options, and one thing about highlights that many people get wrong.
Quick answer
Open the PDF Editor, upload your PDF, choose Highlight, drag over the part you want to mark, pick a color from the small toolbar that appears, and click Download.
How to highlight text in a PDF: step by step
Step 1: Open the editor. Go to the PDF Editor in any browser. No signup is needed.
Step 2: Upload your PDF. Click the box that says "Click or drag a PDF here to start editing" or drag your file into it. The editor accepts files up to 20MB. If your PDF is larger, compress it first.
Step 3: Choose the Highlight tool. On a computer, click Highlight in the menu on the left. On a phone, the toolbar at the bottom scrolls sideways, and Highlight is in the first half, next to Text, Edit text, Image and Shape.
Screenshot: the Highlight tool selected, with the toolbar over a highlighted paragraph.
Step 4: Drag over the part you want to mark. Press and drag across the text. A colored box appears over it. In our test the highlight started out yellow.
Step 5: Use the toolbar. As soon as you let go, a small toolbar appears above the highlight. It has a color button, a copy button, a lock button and a trash button. We explain the ones we tested below.
Step 6: Download. Click Download to save the highlighted PDF to your device.
Changing the color
The color button in the toolbar opens a small color panel. It offers swatches under "Colors from this PDF", and a Pick any color option if you want something else. This is useful when you want different colors for different meanings, such as yellow for key points and green for things to check.
The toolbar: copy and delete
- Copy: this makes a duplicate of the highlight. It helps when you want another box of the same size and color somewhere else on the page.
- Trash: this removes the highlight. You can also use Undo and Redo at any time.
What we saw in the downloaded file
We did not stop at how the highlight looks on screen. We downloaded the PDF and checked what was inside.
- The text under the highlight is still there. The highlighted words can be selected, copied and searched, just like the rest of the page.
- The highlight is see-through. It is drawn at about 45 percent opacity with a multiply effect, which is how a real highlighter pen works, so dark text stays dark and easy to read.
- It is part of the page. The file contains no separate highlight comments. The color box is drawn onto the page itself.
Important: a highlight does not hide anything
Because the text under a highlight stays in the file, highlighting is for marking, not for hiding. If you want to remove private details such as a phone number or an ID, use the Redact tool instead.
Does it work with Hindi, tables and phones?
Yes. We highlighted English text, a Hindi paragraph and a table, and all of them worked. We also tried it on a phone, and highlighting worked there too. If you also want to type Hindi into a PDF, read our guide on writing Hindi in a PDF.
Tips for cleaner highlights
- Zoom in first. It is easier to drag exactly over a line when the page is enlarged.
- Use one color per meaning. For example, yellow for key points and green for items to check.
- Keep the original file. Save a copy of the PDF before you edit it.
- Mark up more than text. For pen marks, arrows and shapes, see our guide to drawing on a PDF.
- Need to type notes too? Add them with the Text tool. Our free PDF editor guide covers everything the editor can do.
Is it safe?
The PDF Editor runs in your browser, so your PDF is not uploaded to a server while you edit. The tool page also states that your file stays private. Still, work on a device you trust, and keep track of the finished file after you download it.
If something does not work
- The highlight is in the wrong place: click its trash button, or use Undo, and drag again.
- The color is too dark to read the text: open the color button and pick a lighter swatch.
- The PDF will not open: if it is password-protected and you are allowed to open it, use Unlock PDF first.
- The file is too big: compress the PDF and try again.