Annotate PDF Online

Annotate PDF Online serves the common need to mark up a document for review without pushing it through a hosted annotation service. This route uses the local Plain Tools annotation workspace, so you can highlight, draw, or add text notes and then export the review copy directly from the browser.

What this tool does

Annotate PDF pages locally with pen, highlight, and text tools in a browser review workspace.

This landing page uses the same underlying workflow as Annotate PDF. The core operation runs locally in your browser, so the file stays on your device during processing.

Step-by-step instructions

1Upload the PDF and open it in the local annotation workspace.
2Add highlights, notes, or pen marks where reviewers need context or decisions.
3Export the annotated copy locally and keep the clean source file separate from review output.

Tool workspace

Open the live tool here or jump to Annotate PDF.

Basic PDF annotation

Draw pen marks, add transparent highlights, and place text labels per page. Processing runs fully in your browser and files never leave your device.

Drop a PDF here, or click to browse

Local-only annotation workspace with no upload step

Click or drop files to continue

Annotation tools

Upload a PDF to start annotating.

Stroke width (4px)

Pen colour

Canvas overlay (page 1)

Draw or place text directly on the page overlay. Highlights use transparent yellow by default.

Apply and download

Embed all annotations into a new PDF and download the annotated result locally.

Why Plain.tools is private

No upload step

The core file workflow on this page runs in your browser, so the document does not need to be sent to a Plain.tools server to complete the task.

Easy to verify

You can inspect browser network requests yourself while using the tool and confirm whether file bytes are being transmitted.

Built for task flow

The aim is to let you finish a PDF job quickly without account friction, upload queues, or hidden processing steps that are hard to audit.

Limitations and checks

Annotations are for review and collaboration, not for irreversible data removal.
Keep a separate clean source file so comments and highlights do not become your only master copy.
Review the exported file in another viewer if the annotated copy will be sent outside your team.

FAQ

Can I annotate a PDF online without uploading it?

Yes. The annotation workspace runs locally in your browser, so the document stays on your device during the core workflow.

Should I annotate the only copy I have?

No. Keep a clean source version and export a separate annotated copy for review or collaboration.

Is annotation the same as redaction?

No. Annotation adds marks for review. It does not remove underlying content the way real redaction should.