This should work just fine. Replace the Console.WriteLine(...) with the appropriate code for what you want to do with the lines of text.
Good luck!
var filePath = "C:\\MyPath\\EmailId.txt";
var fileText = System.IO.File.ReadAllText(filePath);
var lines = fileText.Split(new string[] {Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries);
lines = lines.Select(p => p.Trim())
.Where(p => !string.IsNullOrWhiteSpace(p) &&
!p.StartsWith("#", StringComparison.OrdinalIgnoreCase))
.ToArray();
foreach (var line in lines)
Console.WriteLine(line);