// Directory path for input and output files.
string dirPath = "D:\\Download\\";

// Load your sample CSV file inside the Workbook object.
Aspose.Cells.Workbook wb = new Aspose.Cells.Workbook(dirPath + "sampleConvertCSVToExcelFormats.csv");

// Save CSV file to XLSB format.
wb.Save(dirPath + "outputConvertCSVToExcelFormats.xlsb", SaveFormat.Xlsb);