How to highlight text in a PDF

Highlighting text in a PDF is quickest in PDF by Zaweba by selecting the words and pressing Ctrl+Shift+L. The same marks are in the Comment menu, along with underline, strikethrough and squiggly underline, and Comment, Highlight an area marks a region instead of words. The app is free and works offline on Windows.

A highlight in a PDF is a comment, which means it sits on top of the page rather than changing the text, so it can be changed, filtered or removed later.

Marking words

Select the text you want with the text selection tool, just as you would in a web page. Then press Ctrl+Shift+L, or choose Highlight from the Comment menu. The words are marked in colour.

The other text marks work the same way. Underline draws a line under the selected words, strikethrough draws a line through them, and squiggly underline gives a wavy line, the kind often used to flag a spelling or wording question. Pick whichever suits what you mean. A highlight says look at this; a strikethrough says take this out.

Highlighting an area

Some things can't be selected as text. A scanned page is a picture, and so is a chart or a photograph. For those, use Comment, Highlight an area and drag a box over the part you mean. It's also handy for marking a whole table or a block of a drawing.

If a scanned document needs real word highlights, it needs text first. Once the page has been through text recognition, the words can be selected and marked like any other.

Changing colours and adding a note

Comment, Properties changes the colour, opacity, author and subject of a comment, with a properties bar under the Comments list. Colour is useful when several people review the same file, or when you want one colour for things to check and another for things that are fine.

Double-clicking a highlight opens its pop-up note beside it, showing the author, date, words and any replies. Type your remark there and the highlight carries it, so a reader sees both what you marked and why.

Keeping track of what you marked

On a long document, the Comments panel is where highlights become useful rather than just colourful. It lists every comment with replies, status and checkmark, and you can search, filter by kind, author or status, and sort by page, author, date, kind or colour. Filtering to highlights shows every passage you marked in one list, and clicking one takes you there.

When you've finished, you can make a summary PDF of the comments, export them as XFDF or FDF to share without the whole document, or flatten them into the pages so they print as part of the page.

Small habits that help

Highlight less than you think you need. A page where every other line is yellow tells the reader nothing. A few marks with a short note each are far more useful.

Set the name that appears on your comments before you start, so other people know who marked what. If several people mark the same copy, everyone's work stays told apart.

PDF by Zaweba doesn't send your documents anywhere, so you can mark up contracts, reports and coursework on your own PC without uploading them.