How To Edit Annotations In A PDF Online For Free
Learn how to add, delete, or modify PDF annotations without a monthly subscription. This guide covers free tools for highlighting, commenting, and marking up documents directly in your browser
Background
PDF annotations are interactive or visual elements that sit on top of a page's content without altering the underlying text or images. They are the standard way to mark up a document, leave feedback, highlight important passages, draw attention to a region, or embed clickable links. Annotations are part of the PDF specification, so they travel with the file and are visible in any conforming reader.
There are many annotation types defined by the PDF spec, but the ones you will encounter most often in everyday documents are link, circle, square, highlight, ink, and comment. Each type has a distinct purpose and appearance, all covered below.
- Use link annotations to create clickable areas that open a URL, email, or jump to a specific destination
- Use circle or square annotations to draw attention to a region on the page
- Use highlight annotations to mark text with a colored overlay
- Use ink annotations to draw freehand marks directly on the page
- Use comment annotations to leave a note that readers can expand and read
- All of the above can be added and edited in the Edit PDF tool, locally in your browser, no uploads, no account required
Annotation types
Link
A link annotation creates an invisible clickable area on the page. When a reader clicks that area in a PDF viewer, it triggers a destination you configured: an external URL, an email address, or a specific page and position within the same document. The annotation itself is not visible on the page, it is purely interactive.
This makes link annotations ideal for table-of-contents navigation, citations and source references, contact pages, and any document you want to make more interactive without changing its visual appearance. For more information on this topic, see How To Add A Clickable Link In A PDF Online For Free.
Circle
A circle annotation draws an ellipse outline over a region of the page. It is one of the simplest ways to draw a reader's eye to a specific area, whether that is a chart data point, a word in a paragraph, or a figure in a table. The circle sits on top of the page content without covering or modifying it.
You can customize the stroke color and width to match the visual style of your document. A thin red circle is common for review and proofreading workflows, while a thicker colored border can work well for instructional or marketing materials. You can also stretch it however you want to form an ellipse, or oval shape.
Square
A square annotation (also called a rectangle annotation in the PDF spec) draws a rectangular outline over a region. It serves the same visual purpose as a circle, but the straight edges make it better suited for highlighting rows in a table, sections of a form, or rectangular areas of content you want to frame.
Like the circle, the square annotation supports customizable stroke color and width, and leaves the underlying content untouched.
Highlight
A highlight annotation overlays a semi-transparent color band over text to mark it as important. It is the digital equivalent of a physical highlighter pen and is one of the most commonly used annotation types in reading and review workflows. Highlights draw a reader's attention without obscuring the text below.
You can choose the highlight color, with yellow being the default in most tools, but other colors like green, blue, or pink can be useful when you want to categorize different types of information across a document.
Ink
An ink annotation records a freehand drawing path directly on the page. Unlike shapes or highlights, ink follows the exact stroke you draw with your mouse or touch input, making it the most expressive annotation type. You can use it to circle something irregularly, draw an arrow pointing to content, sketch a quick diagram, or write a short handwritten note.
Ink annotations support customizable stroke color and width, giving you control over how prominent the drawing appears relative to the page content below it.
Comment
A comment annotation (also called a sticky note or text annotation) places a small icon on the page that expands into a text note when clicked. It is the standard annotation type for review and collaboration workflows, letting you leave feedback, questions, or context attached to a specific location without altering the document content.
Comment annotations are widely supported across PDF readers, so a note you add will be visible to anyone opening the file in Adobe Acrobat, a browser, or any other compliant viewer.
Edit tool
The Edit PDF tool is where you add and edit all of the annotation types above. Open your PDF, and use the toolbar's annotation dropdown to select the type you want to add. Each annotation type has its own set of options in the right-side inspector panel where you can adjust color, stroke width, and other properties after placing it on the page.
To edit an existing annotation, click on it to select it and the inspector panel will load its current properties. You can reposition it by dragging, resize it with the handles, or update any property from the panel. To delete an annotation, select it and use the delete action button in the right panel or press the Delete key.
Everything runs locally in your browser. Your PDF is never uploaded to any server, no account is required, and no watermark is added to your file.
Tips
- Selecting overlapping annotations: If annotations overlap, click the top-most one first, then use the layer buttons in the right panel to bring the one you want forward so you can select it.
- Duplicate for consistency: Use the duplicate action button in the right panel to copy an annotation and reuse it elsewhere on the page rather than drawing a new one from scratch each time.
- Invisible link areas: Link annotations are invisible in the finished PDF. If you want a visual indicator, place a circle or square annotation underneath the link to make the clickable area visible to readers.
- Layer: Since annotations sit on top of the page content, they will always be visible and cannot be accidentally hidden behind other elements.
- Password-protected PDF? You will need the document password to open and edit it. The editor will prompt you when you upload the file.
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