> 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/xamarin/digital-signature/signature/sig-types.md).

# Types of digital signatures supported in a PDF

Learn about the different types of signatures supported in a PDF document - Certification, Usage Rights, and Approval signatures. Explore the Apryse SDK for working with digital signatures as per the

A PDF document allows multiple types of signatures, each serving a different purpose. The below table lists the different types of signatures supported in a PDF document.

| Signature Type          | Signatures allowed in a document (up to) | Description                                                                                                                                             |
| ----------------------- | ---------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Certification signature | 1                                        | Certifies the document, similar to notarizing a paper document.                                                                                         |
| Usage rights signature  | 1                                        | (***Deprecated***) Represents a 'Usage Rights' signature, which determines the types of modifications that are allowed to be performed on the document. |
| Approval signature      | No limit                                 | Represents an approval of the document, when it is used as part of an approval workflow.                                                                |

The Apryse SDK provides a high-level API for working with digital signatures as laid out in the PDF specification. For more detail, refer to section 12.8 of the PDF 2.0 standard.

We support all three types of signatures in a PDF document.


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