// LineWidth property ets the border width in points. builder.Font.Border.LineWidth = 0.5d; // LineStyle specifies line style of a Border. builder.Font.Border.LineStyle = LineStyle.DashDotStroker; // Call Size property to set the size of the font. builder.Font.Size = 16; // Name property is used to set the name of the font. builder.Font.Name = "Arial"; // Make your text bold by calling Bold property builder.Font.Bold = true; builder.Write("Text surrounded by border."); builder.Writeln(); // call the save method to save the MS Word file doc.Save("./output.docx");