How to Highlight a PDF

Highlight a PDF in three steps

1. Open the file in the SmartPDF editor.
2. Choose Highlight (shortcut H). Pick a color — yellow, green, blue, pink or orange — and adjust opacity if you like.
3. Drag across the words you want to mark. Repeat for as many passages as you need; the tool stays active until you choose another one. A single click adds a highlight bar that you can then resize.

To change a highlight, switch to Select, click it, and change its color or opacity, drag it, or resize it from a corner. Press Delete to remove it, or use the Erase tool to remove several quickly.

Area highlights: how they work

SmartPDF highlights a rectangular area rather than snapping to individual letters. That has two practical effects:

• It works on every page, including scanned documents and images where there is no selectable text.
• For a passage that spans several lines, draw one highlight per line for the neatest result.

Highlights are blended with the page so the text underneath stays dark and readable, both on screen and in the downloaded PDF.

A simple color system for studying and review

• Yellow — key ideas and definitions.
• Green — evidence, examples and figures.
• Blue — questions or things to look up.
• Pink — problems, risks or items that need a reply.

Keep it to two or three colors per document; highlighting everything means nothing stands out. Combine highlights with arrows or a short text note in the margin when you need to explain why something matters.

Highlighting on a phone or tablet

Tap Highlight in the bottom tool bar, then drag with one finger. While a drawing tool is active, one-finger drags draw instead of scrolling — switch back to Select to scroll freely. Zooming in first makes it easier to cover exactly the right words.

Will others see my highlights?

Yes. Highlights are written into the downloaded PDF, so they appear in any PDF reader, in print, and for anyone you share the file with. Because they’re part of the page content, they aren’t listed as separate comments in a reader’s annotation panel.