# Overview xlswriter is a PHP C extension for reading and writing Excel 2007+ XLSX files. The English documentation is organised by feature: install the extension, walk through the [quick start](/english/quick-start.md) for both writing and reading, then dive into the topic that matches the task — cell content, worksheet management, styling, charts, conditional formatting, data validation, Excel tables, page setup, workbook properties, defined names, sheet protection, the reader API, CSV conversion and helper utilities. For the rationale behind the project and benchmarks, see [Why use xlswriter](/readme.md). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://xlswriter-docs.viest.me/english/en.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.