Edit Digital Signatures in a PDF File

using (Signature signature = new Signature("sampleSigned.pdf"))
{
    TextSearchOptions options = new TextSearchOptions();
    // search for text signatures in document
    List signatures = signature.Search(options);
    if(signatures.Count > 0)
    {
        TextSignature textSignature = signatures[0];
        // change Text property
        textSignature.Text = "John Walkman";
        // change position
        textSignature.Left = textSignature.Left + 10;
        textSignature.Top = textSignature.Top + 10;
        // change size. Please note not all documents support changing signature size
        textSignature.Width = 200;
        textSignature.Height = 100;
        bool result = signature.Update(textSignature);
        if(result)
        {
            Console.WriteLine($"Signature with Text '{textSignature.Text}' was updated in the document ['{fileName}'].");
        }
        else
        {
            Console.WriteLine($"Signature was not updated in  the document! Signature with Text '{textSignature.Text}' was not found!");
        }
    }
}