---
title: "Essential PDF annotation types explained | Nutrient .NET SDK"
canonical_url: "https://www.nutrient.io/guides/dotnet/annotations/introduction-to-annotations/annotation-types/"
md_url: "https://www.nutrient.io/guides/dotnet/annotations/introduction-to-annotations/annotation-types.md"
last_updated: "2026-05-21T17:12:02.199Z"
description: "Discover the most common types of PDF annotations, including text markup, sticky notes, and link annotations for effective document collaboration."
---

# Understanding common types of PDF annotations

The most common types of PDF annotations are:

- Text markup annotations — These annotations are used to highlight or underline specific text within a document. They include highlight, underline, and strikethrough annotations.

- Text box annotations — Text box annotations enable users to add additional text or comments to specific areas of a document. They appear as rectangular boxes that can be placed anywhere on the page.

- Sticky notes — Sticky notes are small, customizable pop-up windows that can be attached to specific points on a page. They’re commonly used for leaving comments, providing feedback, or adding supplementary information.

- Link annotations — Link annotations enable the creation of hyperlinks within a PDF document. They can be used to link to external websites, other pages within the same document, or specific locations within the document.

- Stamp annotations — Stamp annotations are used to apply predefined graphical images — such as signatures, company logos, and official seals — onto a PDF page.

- Drawing annotations — These annotations enable users to draw shapes, lines, arrows, or freehand sketches directly on a PDF document. They can be used for highlighting areas of interest, adding visual explanations, or creating diagrams.

- File attachments — File attachment annotations enable users to attach additional files — such as images, documents, and multimedia files — to a PDF document. These attachments can be accessed and opened by users viewing the PDF.

---

## Related pages

- [Understanding PDF and XMP annotations for collaboration](/guides/dotnet/annotations/introduction-to-annotations/what-are-annotations-pdf.md)
- [Understanding bounding boxes in PDF annotations](/guides/dotnet/annotations/introduction-to-annotations/bounding-boxes.md)
- [What are XMP annotations?](/guides/dotnet/annotations/introduction-to-annotations/what-are-annotations-xmp.md)