Read excel file in .Net 6

public void ReadExcel(string filePath)
{
  var fileExt = Path.GetExtension(filePath);
  if (fileExt == ".xls")
  {
    //...
  }
  else if (fileExt == ".xlsx")
  {
    //...
  }
  else
  {
    throw new Exception("Wrong file type");
  }
}