// Create a new workbook Workbook workbook = new Workbook(); IWorksheet worksheet = workbook.getWorksheets().get(0); // use Name property to set font name. worksheet.getRange("A1").setValue("Calibri"); worksheet.getRange("A1").getFont().setName("Calibri"); // use ThemeFont property to set font name. worksheet.getRange("A2").setValue("Major theme font"); worksheet.getRange("A2").getFont().setThemeFont(ThemeFont.Major); // Save to an excel file workbook.save("FontName.xlsx");