PDF Annotator
Highlight, underline and add notes.
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About PDF Annotator
PDF Annotator lets you mark up a document the way you would with a pen. Highlight important lines, underline key words and add notes next to the text. When you are done, save the PDF with your marks in place. Everything runs in your browser, so the file stays on your phone or computer.
Students use it to mark lecture notes and past papers before exams. Office workers use it to review a contract or report and point out what needs to change. Teachers can mark an assignment and send it back. Anyone who opens the saved file will see your highlights and notes.
How to use PDF Annotator
- Open your PDF in the annotator.
- Choose highlight, underline or note, then mark the page.
- Download the PDF with your annotations saved.
Why use PDF Hydra
- Highlight textMark important lines in color so they are easy to find again.
- Underline key wordsDraw attention to terms, dates or amounts without changing the text.
- Add notesWrite comments and questions right on the page for yourself or others.
- No upload neededThe annotator works in your browser, so your document never goes to a server.
Frequently asked questions
How do I highlight text in a PDF for free?
Open your file in PDF Annotator, choose the highlight tool and drag over the text. Then download the PDF to keep your highlights.
Will other people see my notes?
Yes. Your highlights, underlines and notes are saved in the PDF. Anyone who opens the file will see them.
Can I annotate a PDF on my phone?
Yes. The annotator works in the browser on phones, tablets and computers. You do not need to install an app.
How can I stop my notes from being changed?
After you annotate, run the file through Flatten PDF. This locks the notes into the page so they cannot be edited or removed easily.