---
title: "Understanding data formats in forms | Document Engine guide"
canonical_url: "https://www.nutrient.io/guides/document-engine/forms/introduction-to-forms/data-formats/"
md_url: "https://www.nutrient.io/guides/document-engine/forms/introduction-to-forms/data-formats.md"
last_updated: "2026-06-08T09:14:14.341Z"
description: "Explore essential data formats for forms. Enhance your applications with best practices for effective data management and structuring."
---

# PDF form submission and data formats

Under the hood, PDF form elements are a type of PDF annotation called “widget” annotations. They’re used to implement interactive form elements, such as buttons, checkboxes, combo boxes, and more.

Widgets that can hold a value — like checkboxes, combo boxes, and text fields — store their data separately in an entity called a form field. All data formats Nutrient supports for encoding annotations are designed to also encode the values of form fields. See our [annotation data formats](https://www.nutrient.io/guides/document-engine/annotations/introduction-to-annotations/data-formats.md) guide to learn more.
---

## Related pages

- [Supported PDF form fields](/guides/document-engine/forms/introduction-to-forms/form-fields.md)
- [Understanding PDF forms and their benefits](/guides/document-engine/forms/introduction-to-forms/what-are-forms.md)