PDFsharp & MigraDoc Foundation

var section = doc.AddSection();
      section.PageSetup.DifferentFirstPageHeaderFooter = true;

      var image = section.Headers.FirstPage.AddImage("logo.png");
      image.Width = "4cm";
      image.LockAspectRatio = true;
      image.RelativeVertical = RelativeVertical.Line;
      image.RelativeHorizontal = RelativeHorizontal.Margin;
      image.Top = ShapePosition.Top;
      image.Left = ShapePosition.Right;

      // doc content

      var heading = section.AddParagraph("This is a heading");

paragraph.Format.SpaceBefore = "20mm";

paragraph.Format.LineSpacingRule = LineSpacingRule.Exactly;
paragraph.Format.LineSpacing = "20mm";