Highlight, underline and annotate a PDF
Mark the important lines in a paper, textbook or contract as you read. The highlighter lets the text show through, even when you paint over it.
Highlighting
- Open your PDF and choose Highlighter in the toolbar (shortcut H).
- Drag over the line you want to emphasize and a block of color is painted.
- Change the color with the round swatches in the style bar, and adjust the strength with the Opacity slider.
- If you painted the wrong spot, press Ctrl+Z.
The highlighter blends multiplicatively with what's underneath. On white paper that gives dark text on a yellow background, and the text stays readable on darker backgrounds too. (The fill of an ordinary shape does hide text, so use the highlighter for emphasis.)
Underlines, arrows and circles
- Underline — use Line (L) from the Shapes menu along the bottom of a line. A thin width of 1–2 looks natural.
- Arrow — Arrow (A) in the Shapes menu points at what you want to explain.
- Circles and boxes — draw an ellipse (O) or rectangle (R) and set the fill to None to keep only the outline.
- Handwritten marks — the Draw tool (P) is good for stars and wavy underlines.
Adding notes
Use the Text tool (T) to write a short note in the margin or beside a line. A smaller size (8–10) in a distinct color, such as purple or red, sets it apart from the body text.
A color convention for reviews
| Color | Example meaning |
|---|---|
| Yellow | Important |
| Green | Checked / agreed |
| Pink / red | Question or needs change |
If several people review a document, agree on what each color means beforehand. The table is only an example; there is no standard.
Before you save
- When you press Download, your marks are merged into the PDF. They look the same in any viewer, but you can no longer remove or move them individually later.
- While you work, you can select a mark with the Select tool (V), move it, or delete it with the Delete key.
- Highlighting does not remove text. To hide sensitive content, use the redact tool.