using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
{
Document doc = new Document(PageSize.A4, 30f, 30f, 30f, 30f);
PdfWriter writer = PdfWriter.GetInstance(doc, ms);
doc.Open();
BaseFont baseFont = BaseFont.CreateFont("C:\\Windows\\Fonts\\arial.ttf", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
//Заголовок
PdfContentByte cb = writer.DirectContent;
cb.Rectangle(10f, 10f, doc.PageSize.Width - 20f, doc.PageSize.Height - 20f);
cb.SetFontAndSize(baseFont, 13);
cb.BeginText();
cb.ShowTextAligned(
PdfContentByte.ALIGN_CENTER, "Отчёт", 300f, doc.PageSize.Height - 30f, 0);
cb.EndText();
cb.Stroke();
doc.Close();
}