PM> Install-Package Spire.PDF

using Spire.Pdf;
using Spire.Pdf.AutomaticFields;
using Spire.Pdf.Graphics;
using System.Drawing;

namespace AddHeaderToExistingPdf
{ 
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument doc = new PdfDocument();

            //Load a PDF file
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\TargetMarket.pdf");

            //Load an image for the header
            PdfImage headerImage = PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\logo.png");

            //Get image width in pixel
            float width = headerImage.Width;

            //Convert pixel to point 
            PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
            float pointWidth = unitCvtr.ConvertUnits(width, PdfGraphicsUnit.Pixel, PdfGraphicsUnit.Point);

            //Specify text for the header
            string headerText = "E-iceblue Tech\nwww.e-iceblue.com";

            //Create a true type font
            PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Times New Roman", 12f, FontStyle.Bold), true);

            //Create a brush
            PdfBrush brush = PdfBrushes.Purple;

            //Create a pen
            PdfPen pen = new PdfPen(brush, 1.0f);

            //Create a creation date field
            PdfCreationDateField creationDateField = new PdfCreationDateField(font, brush);
            creationDateField.DateFormatString = "yyyy-MM-dd";

            //Create a composite field to combine static string and date field
            PdfCompositeField compositeField = new PdfCompositeField(font, brush, "creation time: {0}", creationDateField);
            compositeField.Location = new Point(55, 48);

            //Loop through the pages in the document
            for (int i = 0; i < doc.Pages.Count; i++)
            {
                //Get specific page
                PdfPageBase page = doc.Pages[i];

                //Draw the image on the top blank area
                page.Canvas.DrawImage(headerImage, page.ActualSize.Width - pointWidth - 55, 20);

                //Draw text on the top blank area
                page.Canvas.DrawString(headerText, font, brush, 55, 20);

                //Draw a line on the top blank area
                page.Canvas.DrawLine(pen, new PointF(55, 70), new PointF(page.ActualSize.Width - 55, 70));

                //Draw the composite field on the top blank area
                compositeField.Draw(page.Canvas);
            }

            //Save to file
            doc.SaveToFile("AddHeader.pdf");
            doc.Dispose();
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.AutomaticFields
Imports Spire.Pdf.Graphics
Imports System.Drawing
 
Namespace AddHeaderToExistingPdf
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a PdfDocument object
            Dim doc As PdfDocument =  New PdfDocument() 
 
            'Load a PDF file
            doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\TargetMarket.pdf")
 
            'Load an image for the header
            Dim headerImage As PdfImage =  PdfImage.FromFile("C:\\Users\\Administrator\\Desktop\\logo.png") 
 
            'Get image width in pixel
            Dim width As single =  headerImage.Width 
 
            'Convert pixel to point 
            Dim unitCvtr As PdfUnitConvertor =  New PdfUnitConvertor() 
            Dim pointWidth As single =  unitCvtr.ConvertUnits(width,PdfGraphicsUnit.Pixel,PdfGraphicsUnit.Point) 
 
            'Specify text for the header
            Dim headerText As String =  "E-iceblue Tech\nwww.e-iceblue.com" 
 
            'Create a true type font
            Dim font As PdfTrueTypeFont =  New PdfTrueTypeFont(New Font("Times New Roman",12f,FontStyle.Bold),True) 
 
            'Create a brush
            Dim brush As PdfBrush =  PdfBrushes.Purple 
 
            'Create a pen
            Dim pen As PdfPen =  New PdfPen(brush,1.0f) 
 
            'Create a creation date field
            Dim creationDateField As PdfCreationDateField =  New PdfCreationDateField(font,brush) 
            creationDateField.DateFormatString = "yyyy-MM-dd"
 
            'Create a composite field to combine static string and date field
            Dim compositeField As PdfCompositeField =  New PdfCompositeField(font,brush,"creation time: {0}",creationDateField) 
            compositeField.Location = New Point(55, 48)
 
            'Loop through the pages in the document
            Dim i As Integer
            For  i = 0 To  doc.Pages.Count- 1  Step  i + 1
                'Get specific page
                Dim page As PdfPageBase =  doc.Pages(i) 
 
                'Draw the image on the top blank area
                page.Canvas.DrawImage(headerImage, page.ActualSize.Width - pointWidth - 55, 20)
 
                'Draw text on the top blank area
                page.Canvas.DrawString(headerText, font, brush, 55, 20)
 
                'Draw a line on the top blank area
                page.Canvas.DrawLine(pen, New PointF(55, 70), New PointF(page.ActualSize.Width - 55, 70))
 
                'Draw the composite field on the top blank area
                compositeField.Draw(page.Canvas)
            Next
 
            'Save to file
            doc.SaveToFile("AddHeader.pdf")
            doc.Dispose()
        End Sub
    End Class
End Namespace