How to generate an Excel workbook.

excel.cs

namespace Playground.Sandbox
{
    using System.IO;

    using OfficeOpenXml;

    public static class Program
    {
        public static void Main()
        {
            var file = new FileInfo("MyFile.xlsx");

            using (var package = new ExcelPackage(file))
            {
                var sheet = package.Workbook.Worksheets.Add("MySheet");
                sheet.Cells[1, 1].Value = "MyValue";

                package.Save();
            }
        }
    }
}