How to highlight text in a PDF
Updated
Contents
To highlight text in a PDF, open Annotate PDF, add your PDF, and drag across the words you want to mark. Highlight is already chosen when the pages appear, and a see-through yellow bar lands where you drag. Press Apply & download when you are done, and the marked copy downloads.
A highlight here is a rectangle you draw over the words, not a selection of the text itself, so you decide how much it covers: half a line, or a whole paragraph in one drag. If you save it as a comment rather than into the page, it is fitted to the lines of text under it, the way a PDF viewer's own highlight looks.
The PDF is drawn, marked and saved in your browser, so it stays on your device, and there is no account to create. It takes one PDF of up to 100 MB.
Step by step
- 1Open the Annotate PDF tool.
- 2Drop your PDF on the panel that says “Drop your PDF here, or browse”, or click it to choose the file. Its pages appear in a scrolling view, with Highlight already selected in the toolbar.
- 3Drag across the words you want to mark. A single click instead drops a short bar you can stretch afterwards.
- 4To change the colour, use Colour in the panel beside the page; Opacity starts at 40%. With nothing selected, these set the next highlight; to change one already on the page, choose Select, click it, and the panel sets that one. With Select you can also drag a highlight to move it, or drag a handle to resize it.
- 5Under “Highlights, drawings, notes and shapes”, beside Apply & download, keep Flatten into the page, or choose to save markups as comments instead.
- 6Press Apply & download. The copy downloads at once, named after your file: report.pdf becomes report-annotated.pdf. Under Annotated PDF ready, Download annotated PDF saves it again.
Flattened into the page, or saved as comments
Flatten into the page, the choice selected to start, draws each highlight into the page itself, with its colour multiplied over the words so they stay readable. It shows in every viewer and printout, the original text stays selectable, and nothing becomes an image. The cost is that it cannot be taken out later except with an editor that changes page content, so keep the original if you may want an unmarked copy.
Saving markups as comments writes each highlight as a standard PDF highlight annotation instead. Where the box lies over lines of text, it is fitted to them: one band per line, as tall as the line and as wide as your box. Over a picture of text, such as a scanned page, it stays the box you drew. Other PDF apps list it as a comment and let you select, edit or delete it; there are no reply threads here.
Notes, drawings and covers on the same page
Highlight sits in the toolbar's Mark up group, beside Whiteout, Redact, Draw for freehand ink, and Note for a typed note on coloured paper; the Shapes group has Rectangle, Ellipse, Line and Arrow. Anything you place can be moved, resized, restyled or deleted before you apply, and Undo and Redo step back and forward.
Whiteout only paints a white box: the words under it are still in the file, and search, copy and text extraction can find them. Redact removes what lies under its box. Both are always written into the page, even when the other markups are saved as comments, because a comment can be deleted by whoever opens the file. For a document you need to hand over with words removed, Redact PDF also works in your browser and can search the text for what to remove.
Edit PDF opens the same editor on Select, with the same Highlight in its toolbar, for when you also need to change the PDF's own words.
Locked, restricted and signed PDFs
A PDF that needs a password to open has to be unlocked first; Unlock PDF removes the password if you know it, but it runs on our secure server rather than in your browser. A PDF that opens without a password but whose author restricted changes opens here with the author's rules in force: if the author allows comments, highlights are always saved as comments and the copy keeps the author's encryption, and if not, the mark-up tools stay locked. Typing the owner password into the page unlocks every tool for that file.
On an ordinary PDF, the copy is written out as a new file, so an existing digital signature will no longer validate, and the file's Creator and Producer become this site's name. Its pages, text, bookmarks and form fields are otherwise kept.
Common questions
Can I highlight text by selecting it, like in a PDF viewer?
No. You drag a see-through box over the words instead of selecting them. Flattened, it covers exactly the area you draw. Saved as a comment, it fits itself to the lines of text under the box, one band per line, the way a viewer's own text highlight looks.
Can I change the highlight colour?
Yes. Use Colour in the panel beside the page, which opens your browser's colour picker; highlights start yellow at 40% opacity. Set it before you drag to colour the next highlight, or select one already on the page to change just that one.
Can I remove a highlight after saving?
Saved as a comment, yes: a PDF app that edits comments can select and delete it. Flattened, only with an editor that can change page content, because the highlight is drawn into the page. Before you press Apply & download, any highlight can be selected and deleted, or undone.
Can I highlight a scanned PDF?
Yes. A highlight is a box drawn over the page, so it works on a picture of text too. Saved as a comment, it stays the box you drew, because there are no text lines under it to fit to. To make the words searchable as well, run the scan through OCR PDF first, which runs on our secure server rather than in your browser.
Is my PDF sent anywhere when I highlight it?
No. The PDF is read, marked and saved by code running in your browser tab. If you also add a note in a script beyond the Western European character set, the page fetches a Noto typeface from this site to draw it; your PDF is not sent.