# Adding documentation

In this guide, we'll walk through adding documentation for our [fully test](https://helpscout.gitbook.io/hsds-react/contributing/testing) [custom `Strong` component](https://helpscout.gitbook.io/hsds-react/contributing/creating).

We mainly document 2 things for each component, its purpose and its interface.

## Component purpose

A component's description and any notes worth mentioning (limitations, features, etc).

This is written in the stories mdx file.

[See writing stories](https://hsds.helpscout.com/?path=/docs/%F0%9F%8F%A0-welcome-4-writing-stories--page)

## Component interface

AKA props documentation, we use `defaultProps` and `propTypes` to document the component interface, this information is included directly in the component jsx file.

This documentation is automatically turned into a table inside storybook.

\[See writing components]\([(https://hsds.helpscout.com/?path=/docs/%F0%9F%8F%A0-welcome-3-writing-components--page)](https://github.com/helpscout/hsds-react/tree/71458bf2c89cf51e133f77f549e0f884393a3f28/docs/contributing/\(https:/hsds.helpscout.com/?path=/docs/%F0%9F%8F%A0-welcome-3-writing-components--page\)/README.md))

## Next

Let's submit our component for [review](https://helpscout.gitbook.io/hsds-react/contributing/review)!