> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/uwp/low-level-pdf-api.md). # Low-level PDF API - [Low-Level document editing (COS/SDF API) in UWP](https://docs.apryse.com/uwp/low-level-pdf-api/low-level.md): Discover the benefits of working with low-level PDF APIs using Apryse SDK. Gain full access to PDF object model, seamless integration, and unique functionalities for customizing PDF documents. Explore - [Information dictionary: adding custom data to a PDF in UWP](https://docs.apryse.com/uwp/low-level-pdf-api/add-custom.md): Learn how to add custom data to PDF files using the Cos/SDF low-level API with a full code sample. Edit existing documents easily with this step-by-step guide! The Apryse uwp SDK streamlines secure do - [Introduction to PDF file format](https://docs.apryse.com/uwp/low-level-pdf-api/pdf.md): Discover the basic structure of a PDF document in this detailed guide. Learn about the header, body, cross-reference table, and trailer sections that make up a PDF file. Explore the elements that crea - [SDF / COS object model](https://docs.apryse.com/uwp/low-level-pdf-api/sdf.md): Discover the complexities of real-life PDF documents and how to navigate them with Apryse CosEdit. Edit PDFs at the object level with ease using Apryse SDK's SDF/COS level API. Uncover the world of SD - [Filters and streams in UWP](https://docs.apryse.com/uwp/low-level-pdf-api/filters.md): Learn about SDF stream objects and filter pipelines in PDF documents with Apryse SDK. Explore how to efficiently process streams using various filters for data transformation and extraction. The Aprys - [Sample for editing PDFs using basic Cos/SDF API in UWP](https://docs.apryse.com/uwp/low-level-pdf-api/samples.md): Unlock the power of Cos/SDF low-level API to edit PDF files with this informative sample. Learn how to manipulate existing documents efficiently. The Apryse uwp SDK streamlines secure document process - [APIs for low-level PDF document editing in UWP](https://docs.apryse.com/uwp/low-level-pdf-api/apis.md): Discover utility classes for PDF documents in UWP (C#/VB/JS) with pdftron.SDF.Obj and pdftron.SDF.SDFDoc. Enhance your PDF handling capabilities now! The Apryse uwp SDK streamlines secure document pro --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.apryse.com/uwp/low-level-pdf-api.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. 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.