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GroupDocs.Signature for Python via .NET adds, finds, verifies, updates, and removes electronic signatures in PDF, Word, Excel, PowerPoint, OpenDocument, and image files. It supports eight signature types, from a plain text label to a certificate-based digital signature, and works with all of them through one API: the Signature class and an options object per operation. It runs entirely on-premise, needs no Microsoft Office or Adobe Acrobat installation, and ships as a pre-built wheel for Windows, Linux, and macOS.

See the full list of supported formats or browse the Developer Guide for runnable examples of every feature.

Add a signature by passing a sign-options object to Signature.sign(). Each signature type has its own options class that controls the content, appearance, and position of the signature.

• Text signature: text labels, stamps, annotations, stickers, and watermarks, with fonts, colors, opacity, and borders. Text can also be rendered as an image.
• Image signature: a scanned handwritten signature or any picture, with rotation, transparency, and borders.
• Digital signature: certificate-based signatures for PDF, Word, Excel, and PowerPoint documents.
• Barcode signature: a wide range of barcode types, such as Code 128, EAN-13, and Codabar.
• QR code signature: QR codes that carry text, links, emails, or phone numbers.
• Stamp signature: round or square stamp images built from lines of custom text, colors, and widths.
• Form-field signature: add form fields to PDF documents and fill existing ones.
• Metadata signature: hidden signatures stored in the document’s metadata.
• Multiple signatures: several signatures of different types in one call.

List the signatures a document already carries. Signature.search() takes one search-options object per signature type and returns what it finds, with each signature’s position, size, and content.

• Search for signatures: text, image, digital, barcode, QR code, metadata, and form-field signatures, alone or several types at once.

Check that a document carries the signatures you expect. Signature.verify() reports whether the document matches the given criteria, such as the text of a signature or the certificate of a digital signature.

• Verify signatures: text, digital, barcode, and QR code signatures, alone or several types at once.

Signatures found by a search can be changed and saved back to the document: moved, resized, or given new text. They can also be removed one by one, by type, or all at once.

• Update signatures: text, image, barcode, and QR code signatures.
• Delete signatures: text, image, digital, barcode, and QR code signatures, or every signature of a given type.

Render pages to images to show users where a signature goes, and read basic facts about a document (file type, size, page count, and page sizes) to place signatures precisely.

• Generate document pages preview: PNG, JPG, or BMP images of every page or of selected pages.
• Generate signatures preview: an image of a signature before it is added to a document.
• Basic usage: read document information with Signature.get_document_info().

Note

Without a license the library runs in evaluation mode: it processes documents of up to two pages, adds an evaluation line to every page it signs, and masks the values of found signatures. See Evaluation Limitations and Licensing.

Complete walkthroughs that combine several API calls:

• Generate a barcode and sign a document
• Generate a QR code and sign a document
• Sign Excel spreadsheets and their macros
• Sign a password-protected PDF
• Sign documents in a Linux container

The groupdocs-signature-net pip package ships an AGENTS.md file inside the wheel so that AI coding assistants can discover the API surface automatically, and GroupDocs runs a public MCP server for on-demand documentation lookups. See Agents and LLM Integration.

No cloud calls and no outbound network traffic: documents never leave your environment. The wheel bundles the .NET runtime it needs, so nothing else is required on Windows. Linux and macOS need a few system packages; see System Requirements and Running in Docker.