Document doc = new Document();
doc.LoadFromFile("sample.docx");
Document extractPage = doc.ExtractPages(0, 1);
extractPage.SaveToFile("result.docx");

Old:
AddDigitalSignature(X509Certificate2 certificate, string comments, DateTime signTime)

New: 
AddDigitalSignature(string certificatePath, string certificatePassword, string comments, DateTime signTime)

// New Append Audio
Presentation pres = new Presentation();
FileStream from_stream = File.OpenRead(inputFile);
RectangleF audioRect = new RectangleF(50, 50, 100, 100);
IAudio audio = pres.Slides[0].Shapes.AppendAudioMedia(from_stream, audioRect);
// Set the duration of the starting fade for 13s
audio.FadeInDuration = 13000f;
// Set the duration of the ending fade for 40s
audio.FadeOutDuration = 10000f;
pres.SaveToFile(outputFile, FileFormat.Pptx2013);

// Retrieve existing documents
FileStream from_stream = File.OpenRead(inputFile);
Presentation presentation = new Presentation();
presentation.LoadFromStream(from_stream, FileFormat.Auto);
foreach (IShape shape in presentation.Slides[0].Shapes)
{
    if (shape is IAudio)
    {
        IAudio audio = shape as IAudio;
        // Set the duration of the starting fade for 13s
        audio.FadeInDuration = 13000f;
        // Set the duration of the ending fade for 20s
        audio.FadeOutDuration = 20000f;
    }
}
presentation.SaveToFile(outputFile, FileFormat.Pptx2013);

// New Append Audio
Presentation pres = new Presentation();
FileStream from_stream = File.OpenRead(inputFile);
RectangleF audioRect = new RectangleF(50, 50, 100, 100);
IAudio audio = pres.Slides[0].Shapes.AppendAudioMedia(from_stream, audioRect);
// Set the start trimming time 8 seconds
audio.TrimFromStart = 8000f;
// Set the end trimming time 13 seconds
audio.TrimFromEnd = 13000f;
pres.SaveToFile(outputFile, FileFormat.Pptx2013);

// Retrieve existing documents			
FileStream from_stream = File.OpenRead(inputFile);
Presentation presentation = new Presentation();
presentation.LoadFromStream(from_stream, FileFormat.Auto);
foreach (IShape shape in presentation.Slides[0].Shapes)
{
    if (shape is IAudio)
    {
        IAudio audio = shape as IAudio;
        // Set the start trimming time 8 seconds
        audio.TrimFromStart = 8000f;
        // Set the end trimming time 13 seconds
        audio.TrimFromEnd = 13000f;
    }
}
presentation.SaveToFile(outputFile, FileFormat.Pptx2013);

table.Fill.Transparency = 0.5f; // Value range is 1-0, table default color is black
// Need to set specific table color, set color code as follows:
table[0, 0].FillFormat.FillType = Spire.Presentation.Drawing.FillFormatType.Solid;
table[0, 0].FillFormat.SolidColor.Color = Color.Orange;

Presentation ppt = new Presentation();
ppt.LoadFromFile("in.pptx");
//Add a digital signature,The parameters: string certificatePath, string certificatePassword, string comments, DateTime signTime
ppt.AddDigitalSignature("test.pfx", "e-iceblue", "111", DateTime.Now);
ppt.SaveToFile("result.pptx", Spire.Presentation.FileFormat.Pptx2016);
ppt.Dispose();

TSAHttpService timestampService = new TSAHttpService("http://time2.certum.pl");
TSAResponse response = timestampService.Check();
//if it is success to receive tsa token
if (response.Success)
  { formatter.TimestampService = timestampService; }

private void Form1_Load(object sender, EventArgs e)
{
    string pdfDoc = @"test.pdf";
    if (File.Exists(pdfDoc))
    {
        this.pdfDocumentViewer1.LoadFromFile(pdfDoc);
        this.pdfDocumentViewer1.Find("FindedText", Color.Empty);
    }
}
private void before_Click(object sender, EventArgs e)
{
    this.pdfDocumentViewer1.FindPrevious();
}

private void next_Click(object sender, EventArgs e)
{
    this.pdfDocumentViewer1.FindNext();
}