static void Main(string[] args) { //Instantiate PresentationEx class that represents the PPT file Presentation pres = new Presentation(); //Blank slide is added by default, when you create //presentation from default constructor //Adding an empty slide to the presentation and getting the reference of //that empty slide Slide slide = pres.AddEmptySlide(); slide = pres.GetSlideByPosition(2); //Get the font index for Arial //It is always 0 if you create presentation from //default constructor int arialFontIndex = 0; //Add a textbox //To add it, we will first add a rectangle Shape shp = slide.Shapes.AddRectangle(1200, 800, 3200, 370); //Hide its line shp.LineFormat.ShowLines = false; //Then add a textframe inside it TextFrame tf = shp.AddTextFrame(""); //Set a text tf.Text = "Text added dynamically"; Portion port = tf.Paragraphs[0].Portions[0]; port.FontIndex = arialFontIndex; port.FontBold = true; port.FontHeight = 32; //Write the output to disk pres.Write("outAspose.ppt"); }