Signature for Java
Signature for .Net

Sign documents
via .NET API

Sign digital documents and images on any platform using our flexible APIs and app based solutions for programmers and end-users.
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Version 23.8 released
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Sign PDF files in C#

More examples >
// Select PDF document
using (Signature signature = new Signature("sample.pdf"))
{
    // Provide text
    var options = new TextSignOptions("John Smith")
    {
        // Set color
        ForeColor = Color.Red
    };
    // Sign document and save to file
    signature.Sign("signed.pdf", options);
}
dotnet add package GroupDocs.Signature

GroupDocs.Signature Overview

API for performing document signing and related operations in .NET applications

Illustration signature

Adding signatures to business documents in C#

Documents signing: With GroupDocs.Signature for .NET, you can add various types of signatures, such as text, images, barcodes, and digital certificates, to PDF and Office documents. This API allows you to sign your documents with nearly any data type, including hidden metadata.

Processing signed documents

Additional processing: You can perform powerful operations on signed documents using GroupDocs.Signature. This includes searching for existing signatures within business documents and verifying them using specific criteria. Additionally, you can retrieve document information and preview pages through this .NET API.

Customizing results

GroupDocs.Signature for .NET offers extensive customization options. You can precisely position signatures anywhere on a document page and adjust their appearance using a variety of settings. Furthermore, this API supports saving processed documents in a wide range of supported formats.

Platform independence

GroupDocs.Signature for .NET supports the following operating systems, frameworks and package managers

Amazon
Docker
Azure
VS Code
ReSharper
macOS
Linux
NuGet

Supported file formats

GroupDocs.Signature for .NET supports operations with the following file formats.

Microsoft Office formats

  • Word: DOCX, DOC, DOCM, DOT, DOTX, DOTM, RTF
  • Excel: XLSX, XLS, XLSM, XLSB, XLTM, XLT, XLTM, XLTX, XLAM, SXC, SpreadsheetML
  • PowerPoint: PPT, PPTX, PPS, PPSX, PPSM, POT, POTM, POTX, PPTM

Images & Other Formats

  • Portable: PDF
  • Images: JPG, BMP, PNG, TIFF, GIF, DICOM, WEBP
  • Other office formats: ODT, OTT, OTS, ODS, ODP, OTP, ODG

Other formats

  • Web: HTML, MHTML
  • Archives: ZIP, TAR, 7Z
  • Certificates: PFX

GroupDocs.Signature features

Signing PDFs, Office Documents, and Images swiftly and accurately

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Document signing

Add one or multiple supported types of signatures accurately at any specified position on business documents.

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Customize signatures

Utilize features such as color, font, border, rotation, etc., to configure the appearance of signatures.

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Document password protection

Secure certain document types by setting a password after signing.

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Protection from changes

Prevent changes to important business documents after appending a signature with a digital certificate.

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Convert signed files to other formats

Convert signed files to desired formats, such as saving a Word document as a PDF.

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Extract page previews

Extract pages from signed documents as individual images for future processing.

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Signature search in documents

Retrieve information about previously added signatures in specific documents.

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Validate signed documents

Verify the proper signing of documents using validation features.

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Update or delete signatures

Easily reposition specific signatures on a page, modify their text, or delete them without any issues.

Code samples

Some use cases of typical GroupDocs.Signature for .NET operations

Add QR-code to PDF

Adding QR-codes to specific pages of PDF documents can enhance business processes. Below is an example of how to add a QR code using GroupDocs.Signature.

How to put QR code to PDF.

// Load the document to sign
using (Signature signature = new Signature("file_to_sign.pdf"))
{
    // Create QR code options with predefined text
    QrCodeSignOptions options = new QrCodeSignOptions("The document is approved by John Smith")
    {
        // Configure QR code encoding type and position on the page
        EncodeType = QrCodeTypes.QR,
        Left = 100,
        Top = 100
    };
    // Sign the document and save it as the result file
    signature.Sign("file_with_QR.pdf", options);
}

Protecting a DOCX document using a digital certificate

You can Protect a Document using personal or corporate signatures stored as digital certificates. Such protected documents cannot be modified without invalidating the signature.

Here is how to ensure document integrity.

// Load the document to be digitally signed
using (Signature signature = new Signature("file_to_sign.pdf"))
{
    // Specify digital signing options and provide the path to the certificate file
    DigitalSignOptions options = new DigitalSignOptions("certificate.pfx")
    {
        // Set the certificate password
        Password = "1234567890"
    };
    // Sign the document and save it to the desired path
    signature.Sign("digitally_signed.pdf", options);
}

Ready to get started?

Try GroupDocs.Signature features for free or request a license

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