API documentation is a crucial component in the development and integration of software applications. It serves as a technical reference manual that provides detailed instructions on how to use and integrate APIs effectively. Good API documentation outlines essential information such as request and response formats, authentication methods, and usage examples. It enhances the user experience by making it easier for developers to understand the capabilities of an API, leading to higher adoption rates and fewer support queries. By adhering to standards like OpenAPI, developers can create clear, consistent, and maintainable documentation that benefits both users and maintainers alike.