Annotate PDF (Highlight, Comment, Draw)
Highlight and mark text, add notes, text boxes and drawings, or edit existing comments.
Nothing selected
Choose a tool and mark the page, or select a comment to change it.
Shown when the comment is opened in a PDF reader.
Find text to mark
Comments 0
No comments yet. Those already in the PDF appear here too.
Saved as standard PDF annotations: PDF readers show them on the page, and readers with a comments panel — Adobe Acrobat Reader, for example — list them there. The page content itself is not changed.
Your annotated PDF is ready
About the Annotate PDF (Highlight, Comment, Draw)
Review a PDF the way you would on paper — and keep it a real PDF. Highlight, underline, strike out or mark words with a squiggly line by dragging across the text, add sticky notes, text boxes, rectangles, ellipses, lines, arrows and freehand drawings, choose colours and give every mark a comment. The comments a PDF already has are listed too: change their text, recolour highlights and shapes, or delete them.
Everything is saved as standard PDF annotations (ISO 32000-1 §12.5) with an author name, dates and an appearance stream, so PDF readers show them exactly as drawn, and readers with a comments panel — Adobe Acrobat Reader, for example — list them there, where they can be replied to. The page content itself is not changed. Your file never leaves your browser.
How to use it
- Drop a PDF onto the box above, or tap Choose a PDF to annotate.
- Pick Highlight, Underline, Strike out or Squiggly and drag across the words (or tap a single word). To mark every occurrence of a word or phrase, use Find text to mark.
- For notes, shapes and drawings, pick Note, Text box, Rectangle, Ellipse, Line, Arrow or Draw and click or drag on the page.
- Select any mark — on the page or in the Comments list — to type its comment, change its colour, opacity or line width, or delete it. Undo and Redo (Ctrl+Z, Ctrl+Shift+Z) work for every change.
- Type Your name so readers show who made the comments, then press Save PDF and Download.
Examples
Find text to mark: “termination” · Mark in the whole PDF · comment on one of them: “Notice period too short”
Every “termination” highlighted in yellow; the commented one opens a note in the reader and appears in its comments list with your name
Strike out a misspelt word, add a Text box with the correction, an Arrow from one to the other
A red strike-out, a text box and an arrow, all saved as separate comments that the author can resolve one by one
Select the comments you no longer need in the Comments list · Delete
They are removed together with their pop-up notes and replies; the page text is untouched
Common uses
- Studying: highlight key passages and add notes to lecture slides and papers.
- Reviewing contracts, reports and theses with comments that colleagues can see in their own PDF reader.
- Marking up drawings and screenshots with rectangles, arrows and freehand circles.
- Removing or rewording comments in a PDF someone sent you before passing it on.
Highlights that follow the text exactly
When you drag across text, the marks are placed using the exact position of every letter, read from the PDF’s own text — not estimated from the line — so a highlight covers exactly the words you chose, on rotated pages too. They are written as standard text markup annotations with QuadPoints (one quadrilateral per line) and an appearance: highlights are blended with Multiply, like a highlighter pen, so the words stay readable underneath.
Scanned pages are pictures with no text to select: the tool tells you so. Use Rectangle, Draw or a Note there, or first make the scan searchable with PDF OCR.
What happens to the comments already in the PDF
- Every comment in the file is listed with its author and date, page by page. Links and form fields are not comments and are left alone.
- You can change the text of any comment. Highlights, underlines, strike-outs, squiggly lines, rectangles, ellipses, lines and drawings can also be recoloured: they are redrawn in the new colour.
- Delete removes a comment together with its pop-up note and every reply in its thread, so no orphaned replies are left — from the file itself, not just from view. Until you save, Restore brings it back, and Discard changes returns to the comments as they are in the file.
- Stamps, file attachments and other special comments keep their own look; they can be commented on or deleted.
Text boxes and fonts
Text boxes are drawn with Helvetica, a font every PDF reader has, and switch to embedded Noto Sans when you type ₹, Greek, Cyrillic or other characters Helvetica lacks. Lines wrap to the width of the box and the box grows to fit the text. Scripts that need text shaping — Devanagari, Tamil, Arabic and others — can’t be written into a text box correctly; put such text in a comment instead, where readers display it with their own fonts.
Keyboard and screen readers
- Every tool is a button; Find text to mark marks text without a mouse.
- The page can be focused: with a tool chosen, Enter adds a note, text box, shape or line in the middle of the visible page; with a comment selected, the arrow keys move it (Shift: 10 points), Delete removes it and Escape deselects it.
- The Comments list shows every mark with its page and status (New, Edited, Will be deleted, In the PDF); selecting an entry jumps to it.
Limitations
- Text marks need selectable text; scanned pages need OCR first, or use shapes and drawings.
- Existing comments can be retexted, recoloured (most kinds) or deleted, but not moved; your own new marks can be moved and resized until you save.
- Text boxes can’t show scripts that need shaping, such as Devanagari or Arabic; comments can contain any language.
- Password-protected or restricted PDFs must be unlocked first with Unlock PDF.
- Saving rewrites the file, so existing digital signatures will show as invalid; the tool warns you when a file is signed.
- Very large files need plenty of memory and can be slow to open on phones.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
Will other people see my highlights and comments?
Yes. They are standard PDF annotations, so PDF readers show them on the page, and readers with a comments panel (such as Adobe Acrobat Reader) list them with your name, where they can be replied to.
How is this different from the PDF Editor?
The PDF Editor draws text, images and shapes into the page. This tool adds comments: separate annotations that readers can show, hide, list, reply to and delete, and it marks the existing text. To make comments permanent, flatten the PDF afterwards with Flatten PDF.
Can I delete comments that are already in a PDF?
Yes. Select them on the page or in the Comments list and press Delete; their pop-up notes and replies go with them. They are removed from the file itself, not just hidden, so their text can’t be recovered from the saved PDF. The page content is not changed.
Why can’t I highlight text on some pages?
Those pages are images — usually scans — with no text in them. Mark them with shapes or drawings, or run PDF OCR first to add a text layer.
Is my PDF uploaded?
No. The PDF is opened, annotated and saved in your browser; nothing is sent to a server.