sign
Applies a signature to a document using an existing signature field. Supports both digital signatures (with certificate) and electronic signatures (visual only). The behavior depends on what is provided:Certificate + Appearance: Digital signature with custom visual appearance.Certificate only: Digital signature with auto-generated appearance from metadata.Appearance only: Electronic signature (visual only, field is replaced with image/text).Neither: Throws ArgumentException. If the document is not in PDF format and implicit conversion is enabled in the document settings, it will be automatically converted to PDF before signing.
Parameters
The document to sign.
The path where the signed PDF will be saved.
The name of the existing signature form field to use for the signature.
The digital signature options. Can be null for electronic signatures.
The visual appearance of the signature.