Highlight Text in a PDF Online

Highlighting is one of the most natural ways to work with a document — flagging important clauses, marking passages for follow-up, building a personal annotation layer on a report you are studying, or calling a colleague's attention to a specific figure.

This editor detects text runs on each page automatically. Switch to the Highlight tool and every text block becomes a clickable target. Click any block and a highlight bar snaps precisely to the text boundaries — no manual drawing or resizing. Or click anywhere on the page to place a freeform highlight box over images, charts, tables, or any area you want to mark. Highlight color and opacity are fully adjustable per object, so color-coded annotation systems take seconds to set up.

Highlights serve different functions depending on the context. In a contract review, they flag clauses you want to discuss or negotiate. In a research document, they mark findings or citations for later reference. In a report, they call out the key metrics for a colleague who needs the summary version. In a training document, they mark the rules or procedures that matter most for a specific team.

The color customization in this editor makes color-coded highlighting practical. Use yellow for general importance, green for approved or correct content, red for issues, orange for items needing clarification, and blue for references or citations. Each highlight is independently styled, so a multi-color annotation system takes only a few seconds per page to apply.

For academic use — research papers, textbook chapters, reference materials — systematic highlighting during a first read creates a navigable reference layer. The exported annotated PDF preserves all highlights in a portable format that opens correctly in any viewer or study tool that accepts PDFs.

Highlights in this editor are embedded as filled color rectangles — visible in every PDF viewer, printable, and portable across any device or reading context.