This link will help you out completely(the Shortest and Most Elegant way):
PdfPTable tbheader = new PdfPTable(3);
tbheader.TotalWidth = document.PageSize.Width - document.LeftMargin - document.RightMargin;
tbheader.DefaultCell.Border = 0;
tbheader.AddCell(new Paragraph());
tbheader.AddCell(new Paragraph());
var _cell2 = new PdfPCell(new Paragraph("This is my header", arial_italic));
_cell2.HorizontalAlignment = Element.ALIGN_RIGHT;
_cell2.Border = 0;
tbheader.AddCell(_cell2);
float[] widths = new float[] { 20f, 20f, 60f };
tbheader.SetWidths(widths);
tbheader.WriteSelectedRows(0, -1, document.LeftMargin, writer.PageSize.GetTop(document.TopMargin), writer.DirectContent);
PdfPTable tbfooter = new PdfPTable(3);
tbfooter.TotalWidth = document.PageSize.Width - document.LeftMargin - document.RightMargin;
tbfooter.DefaultCell.Border = 0;
tbfooter.AddCell(new Paragraph());
tbfooter.AddCell(new Paragraph());
var _cell2 = new PdfPCell(new Paragraph("This is my footer", arial_italic));
_cell2.HorizontalAlignment = Element.ALIGN_RIGHT;
_cell2.Border = 0;
tbfooter.AddCell(_cell2);
tbfooter.AddCell(new Paragraph());
tbfooter.AddCell(new Paragraph());
var _celly = new PdfPCell(new Paragraph(writer.PageNumber.ToString()));//For page no.
_celly.HorizontalAlignment = Element.ALIGN_RIGHT;
_celly.Border = 0;
tbfooter.AddCell(_celly);
float[] widths1 = new float[] { 20f, 20f, 60f };
tbfooter.SetWidths(widths1);
tbfooter.WriteSelectedRows(0, -1, document.LeftMargin, writer.PageSize.GetBottom(document.BottomMargin), writer.DirectContent);