PDF Annotator

Annotation isn't editing — you're not changing the document, you're adding marks on top. Common reasons:

• Reading and study. Highlight key passages, sticky-note questions for later.
• Reviewing a draft. Mark up a contract with comments before sending feedback.
• Class notes. Highlight readings, add margin notes on a textbook PDF.
• Sharing feedback. Sticky notes on a design PDF for the designer.
• Quick decisions. Strike through outdated paragraphs, circle the budget number.

Annotations are layered on top of the original — toggleable, removable, and easy to clear before sharing if you want.

1. Open PDF Annotator.
2. Drop your PDF.
3. Pick a tool: highlighter, freehand pen, shape, or sticky-note comment.
4. Drop annotations onto the page at the position you specify.
5. Click Save to download the annotated copy.

Annotations stay editable in the saved file — open it again later (in any PDF reader) and the highlights, notes, and strokes are still individually movable. To lock them in permanently, run the output through Flatten PDF.

• Highlight, underline, strikethrough — applied to text spans. Choose a color.
• Freehand pen — draw arbitrary strokes; useful for circles, arrows, hand-drawn emphasis.
• Shapes — rectangles, ovals, lines — for boxing or arrowing specific regions.
• Sticky-note comments — text content tied to a page position; shows on hover in PDF readers.
• Free text — for inline labels and longer margin notes.

All of these are standard PDF annotation types — they're saved into the PDF using the AnnotationDictionary spec, so any compliant PDF reader (Acrobat, Preview, Chrome, Firefox) will display them.

• Annotator = adding non-permanent marks on top: highlights, comments, freehand. Annotations remain a separate layer; the recipient can toggle or remove them.
• Editor = adding permanent content (text, shapes, images) that becomes part of the page when flattened.
• Redactor = permanently removing content — opaque black bars with the underlying text actually destroyed.

For "mark this up so the recipient can see my notes," use the Annotator. For "add a logo and signature line that should look like part of the document," use the Editor.

Two ways to share an annotated PDF:

• As-is — annotations remain editable. The recipient can hide them, toggle them, or remove them. Best for collaborative review.
• Flattened — annotations become permanent page content. The recipient sees them as part of the document; can't toggle them off. Best for sending a final marked-up reference. Run through Flatten PDF after annotating.

• My annotations don't show in some viewers. A handful of basic PDF readers (especially printer driver renderers) ignore the annotation layer. Flatten before sending to such recipients.
• Highlights don't snap to text. The Annotator places rectangles by coordinates, not by selecting text spans. For text-aware highlighting, Adobe Acrobat or macOS Preview handle this better.
• Sticky notes don't appear inline. Sticky notes are collapsed icons in most viewers — hover or click to read the text. To make them always-visible, use Free text instead.
• I want to export just the comments. Not supported in v1 — comments are saved into the PDF itself, not as a separate list.

Annotation often happens to documents you've just received — meaning the unannotated original is sometimes the more-sensitive version. Uploading the source PDF to an online annotator means the original briefly sits on someone else's server, where it could be cached or logged. SwissArmyPDF runs the entire annotate pipeline in your browser using pdf-lib. The file never leaves your device.

• Flatten PDF — lock annotations as permanent page content.
• Merge PDF — combine annotated sections from multiple reviewers.
• Compress PDF — shrink the annotated file for sharing.
• Edit PDF — for permanent additions (vs reviewable annotations).