Export password protected Excel file and encrypt Excel file using EasyXLS library! XLS, XLSX, XLSM, XLSB file in .NET.
https://www.easyxls.com/manual/tutorials/csharp/encrypt-excel-file.html

Export Excel with pivot chart using EasyXLS library! XLS, XLSX, XLSM, XLSB file in .NET.
https://www.easyxls.com/manual/tutorials/csharp/create-excel-pivot-chart.html

Export Excel with pivot table using EasyXLS library! XLS, XLSX, XLSM, XLSB file in .NET.
https://www.easyxls.com/manual/tutorials/csharp/create-excel-pivot-table.html

Export Excel chart using EasyXLS library! XLS, XLSX, XLSM, XLSB file in .NET.
https://www.easyxls.com/manual/tutorials/csharp/create-excel-chart.html