PdfDocument pdf = new PdfDocument();
PdfPageBase page = pdf.Pages.Add();

PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial Unicode MS", 11f), true);
PdfCjkStandardFont font1 = new PdfCjkStandardFont(PdfCjkFontFamily.MonotypeSungLight, 11f);

page.Canvas.DrawString("中國", font, PdfBrushes.Red, 50, 50);
page.Canvas.DrawString("中國", font1, PdfBrushes.Red, 50, 70);

pdf.SaveToFile("result.pdf");

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

namespace Add_Chinese_Characters_to_PDF
{
    class Program
    {
        static void Main(string[] args)
        {
            PdfDocument pdf = new PdfDocument();
            PdfPageBase page = pdf.Pages.Add();
            
            PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial Unicode MS", 11f), true);
            PdfCjkStandardFont font1 = new PdfCjkStandardFont(PdfCjkFontFamily.MonotypeSungLight, 11f);
            page.Canvas.DrawString("中國", font, PdfBrushes.Red, 50, 50);
            page.Canvas.DrawString("中國", font1, PdfBrushes.Red, 50, 70);
            pdf.SaveToFile("result.pdf");
            System.Diagnostics.Process.Start("result.pdf");
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Graphics
Imports System.Drawing

Namespace Add_Chinese_Characters_to_PDF
 Class Program
  Private Shared Sub Main(args As String())
   Dim pdf As New PdfDocument()
   Dim page As PdfPageBase = pdf.Pages.Add()
   Dim font As New PdfTrueTypeFont(New Font("Arial Unicode MS", 11F), True)
   Dim font1 As New PdfCjkStandardFont(PdfCjkFontFamily.MonotypeSungLight, 11F)
   page.Canvas.DrawString("中國", font, PdfBrushes.Red, 50, 50)
   page.Canvas.DrawString("中國", font1, PdfBrushes.Red, 50, 70)
   pdf.SaveToFile("result.pdf")
   System.Diagnostics.Process.Start("result.pdf")
  End Sub
 End Class
End Namespace