Highlight text, add notes, and annotate PDF documents free. Multiple colors, sticky notes, and drawing tools. Perfect for review and study. No signup needed.

Annotation transforms a PDF from something you just read into something you actively engage with. Highlight key passages, add margin notes, flag questions, circle data points — without printing. ## How to Annotate PDF 1. Go to [pdfhub24.com/annotate-pdf](/annotate-pdf) 2. Upload your PDF 3. Select your annotation tool from the toolbar 4. Apply annotations: - **Highlight:** drag across text to mark in colour - **Sticky note:** click to place a comment anywhere on the page - **Underline:** drag across text to underline - **Strikethrough:** drag across text to mark for deletion - **Free draw:** draw circles, arrows, or freehand marks 5. Download your annotated PDF ## Colour Coding for Better Annotations Using different highlight colours for different purposes makes your annotations much more useful: - **Yellow** — important general information - **Blue** — action items or things to follow up - **Green** — agreed points or confirmed information - **Red/Pink** — concerns, disagreements, or errors - **Orange** — quotations to use later A consistent system means you can scan a document and understand your own annotation patterns at a glance. ## Annotating for Document Review For reviewing a colleague's report or a client's document, use sticky notes to add comments that explain your annotations. "Check this figure against Q3 data" is more useful than a highlighted number alone. Keep comments specific and constructive. "This section is unclear" is less useful than "This section jumps from the budget discussion to personnel without a transition sentence." ## Annotated PDFs Stay Compatible Annotations added through PDF HUB 24 are standard PDF annotation objects that display correctly in Adobe Reader, Preview (Mac), Chrome's PDF viewer, and all major PDF applications. The recipient doesn't need any special software.