PdfDocument doc = new PdfDocument();
doc.LoadFromFile(input);
PdfPageBase pdfPageBase = doc.Pages[0];
PdfTextFinder finder = new PdfTextFinder(pdfPageBase);
finder.Options.Strategy = PdfTextStrategy.Simple;

PdfDocument doc = new PdfDocument();
PdfPageBase page = doc.Pages.Add();
string text = "Please add the code picture BehindText=true to set the picture behind text";
PdfSolidBrush solidBrush = new PdfSolidBrush (new PdfRGBColor(Color.Black));
PdfStringFormat format = new PdfStringFormat():
format.HorizontalScalingFactor = 80;
PdfFont font = new PdfFont(PdfFontFamily.TimesRoman, 14f, PdfFontStyle.Regular);
PdfGraphicsState state = page.Canvas.Save();
page.Canvas.DrawString(text, font, solidBrush, 0, 0, format);
page.Canvas.Restore(state):
doc.SaveToFile(outputFile);
doc.Close();

PdfDocument doc = new PdfDocument();
doc.LoadFromFile(inputFile);
doc.ConvertOptions.ApplyPermissionsOptions(true);
StringBuilder sb = new StringBuilder();
    foreach (FileFormat type in Enum.GetValues(typeof(FileFormat)))
        {
            try
                {
                    if (type.ToString().Equals("PDF"))
                    {
                        doc.SaveToFile(outputFile_P, type);
                    }
                    else
                    {
                        doc.SaveToFile(outputFile, type);
                    }
                }
                catch (Exception ex)
                {
                    sb.AppendLine("save to： "+ type +"  :"+ ex.Message);
                }
            }
File.AppendAllText(outputFile,sb.ToString());
doc.Dispose();

Document doc = new Document();
doc.LoadFromFile(fileName);
doc.LayoutOptions.UseHarfBuzzTextShaper = true;
doc.SaveToFile(pdfFileName, Spire.Doc.FileFormat.PDF)

sheet.PivotTables[0].RowFields[0].CustomName = "rowName";
sheet.PivotTables[0].ColumnFields[0].CustomName = "colName";
sheet.PivotTables[0].PivotFields[0].CustomName = "fieldName1";
sheet.PivotTables[0].DataFields[0].CustomName = "dataName";

Presentation ppt = new Presentation();
ppt.LoadFromFile(inputFile);
StringBuilder sb = new StringBuilder();
ISlide slide = ppt.Slides[0];
for (int i = 0; i < slide.Shapes.Count; i++)
 {
     IShape shape = slide.Shapes[i];
     if (shape is IAutoShape)
     {
         IAutoShape autoshape = slide.Shapes[i] as IAutoShape;
         string text = autoshape.TextFrame.Text;
         //obtain the text position information
         PointF point = autoshape.TextFrame.GetTextLocation();
         sb.AppendLine("Shape " + i + "：" + text + "\r\n" + "location：" + point.ToString());
     }
}
File.AppendAllText(outputFile, sb.ToString());
ppt.Dispose();

Presentation ppt = new Presentation();
ppt.LoadFromFile(inputFile);
ISlide slide = ppt.Slides[0];
IAutoShape autoshape = slide.Shapes[0] as IAutoShape;
IList<LineText> lines = autoshape.TextFrame.GetLayoutLines();
for (int i = 0; i < lines.Count; i++)
{
   float ascent= lines[i].Ascent;
   float descent = lines[i].Descent;
}

Presentation ppt = new Presentation();
ppt.LoadFromFile("FreeForm.pptx");
ISlide slide = ppt.Slides[0];
int num = 0;
foreach (IShape shape in slide.Shapes)
{
    byte[] svgByte = shape.SaveAsSvg();
    FileStream fs = new FileStream("shape_" + num + ".svg",FileMode.Create);
    fs.Write(svgByte, 0, svgByte.Length);
    fs.Close();
    num++;
}