Highlight PDF Online Free — Yellow Highlighter Tool

Why highlight text in a PDF?

Reviewing long documents is easier when important text stands out. Highlighting key sections helps you mark notes, identify deadlines, emphasize important clauses, or prepare documents for collaboration without changing the original content.

PDFly lets you highlight text in PDF files directly in your browser. Your documents remain on your device throughout the process, with no account required, no watermark, and no software installation. It works on Windows, Mac, Linux, Android, and iPhone.

Best Practices & Limitations

Tips for best results

Use a consistent color scheme (e.g. yellow for key facts, green for action items) across a document set for faster review later.
Highlight sparingly — over-highlighting defeats the purpose of drawing attention to what matters most.
Combine with Annotate PDF if you need to add a note explaining why a passage is highlighted.

Limitations & when not to use this tool

Highlights sit as a PDF annotation layer — some very old PDF readers may not display them.
Not searchable by highlight color; there's no built-in way to filter pages by which color was used.
For permanent, non-removable emphasis, flatten the PDF afterward.

About highlight PDF

Highlight important text in a PDF so key information is easier to find during reading and review.

Common uses for highlight PDF

Useful for studying, reviewing contracts, research, meeting notes, and marking important passages in long documents.

Tips for using this PDF tool

Use highlights consistently and avoid covering text with opaque marks.

Related PDF tools

Want a step-by-step walkthrough? Read the Highlight PDF guide.

Frequently asked questions

Can I change the highlight color?

Yes. Supported highlight colors can be selected before saving your edited PDF.

Can I highlight scanned PDFs?

Scanned PDFs may require OCR before text can be highlighted accurately. Otherwise, highlighting may work only as an annotation.

Will highlights be visible in other PDF readers?

Yes. Standard PDF highlights are supported by most modern PDF viewing applications.

Can I remove highlights later?

Yes. As long as the PDF remains editable, highlights can usually be modified or removed before flattening the document.

Common workflow

PDF ReaderHighlight PDFAnnotate PDF