> 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/android/digital-signature.md). # Digital signature - [Digital signature library for Android](https://docs.apryse.com/android/digital-signature/signature.md): Discover how the Signature Tool Android allows users to create signature annotations effortlessly. Learn the differences between digital signatures and signature annotations for enhanced document secu - [Using digital signature tool in Android](https://docs.apryse.com/android/digital-signature/digi-sig-tool.md): Sign documents with ease using the DigitalSignature tool in the Tools package. Learn how to enable certificate-based signatures and save signed documents securely. Perfect for PDF viewing and signing. - [Validate Digital Signatures in Android](https://docs.apryse.com/android/digital-signature/digital-signature-validation.md): Learn how to validate signatures in signed documents using the DigitalSignatureListDialog. Add trusted certificates and verify digital signatures easily. The Apryse Android SDK streamlines secure docu - [Sign a PDF document in Android](https://docs.apryse.com/android/digital-signature/sign-pdf.md): Learn how to digitally sign PDF files using the Apryse SDK. Ensure document authenticity with approval signatures and certificates issued by trusted authorities. The Apryse Android SDK streamlines sec - [Adding a certified signature field to a PDF in Android](https://docs.apryse.com/android/digital-signature/certify-pdf.md): Learn how to add a certification signature field to a PDF document and digitally sign it with a full code sample. Certify PDF/A documents for compliance using the digital signature API. The Apryse And - [Verify a signature in Android](https://docs.apryse.com/android/digital-signature/verify-pdf.md): We offer a higher-level document-based API for verifying signatures, as well as a lower-level per-signature API. Page includes code samples. - [Code samples for adding digital signatures to PDFs in Android](https://docs.apryse.com/android/digital-signature/samples.md): Learn how to digitally sign PDF files with this high-level API demo. Check out UI samples and an Android showcase app for more features. Try the digital signature demo now! The Apryse Android SDK stre - [API for digital signatures in Android](https://docs.apryse.com/android/digital-signature/apis.md): Learn how to handle digital signatures in PDF documents using classes like com.pdftron.sdf.SignatureHandler and com.pdftron.pdf.DigitalSignatureField in Android (Java/Kotlin). Master digital signature --- # 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/android/digital-signature.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.