C#/VB.NET: Insertar marcas de agua en Word

PM> Install-Package Spire.Doc

using System;
    using System.Drawing;
    using Spire.Doc;
    using Spire.Doc.Documents;
    
    namespace InsertImageWatermark
    {
        internal class Program
        {
            static void Main(string[] args)
            {
                //Create an object of Document class
                Document document = new Document();
    
                //Load a Word document from disk
                document.LoadFromFile(@"D:\Samples\Sample.docx");
    
                //Insert a text watermark
                InsertTextWatermark(document.Sections[0]);
    
                //Save the document
                document.SaveToFile("InsertTextWatermark.docx", FileFormat.Docx);
            }
            private static void InsertTextWatermark(Section section)
            {
                TextWatermark txtWatermark = new TextWatermark();
                txtWatermark.Text = "DO NOT COPY";
                txtWatermark.FontSize = 50;
                txtWatermark.Color = Color.Blue;
                txtWatermark.Layout = WatermarkLayout.Diagonal;
                section.Document.Watermark = txtWatermark;
    
            }
        }
    }

Imports System
    Imports System.Drawing
    Imports Spire.Doc
    Imports Spire.Doc.Documents
    
    Module Program
        Sub Main(args As String())
            'Create an object of Document class
            Dim document As New Document()
    
            'Load a Word document from disk
            document.LoadFromFile("D:\Samples\Sample.docx")
    
            'Insert a text watermark
            InsertTextWatermark(document.Sections(0))
    
            'Save the document
            document.SaveToFile("InsertTextWatermark.docx", FileFormat.Docx)
        End Sub
        Private Sub InsertTextWatermark(ByVal section As Section)
            Dim txtWatermark As New Spire.Doc.TextWatermark()
            txtWatermark.Text = "DO NOT COPY"
            txtWatermark.FontSize = 50
            txtWatermark.Color = Color.Blue
            txtWatermark.Layout = WatermarkLayout.Diagonal
            section.Document.Watermark = txtWatermark
        End Sub
    End Module

using System;
    using System.Drawing;
    using Spire.Doc;
    using Spire.Doc.Documents;
    
    namespace InsertWatermark
    {
        internal class Program
        {
            static void Main(string[] args)
            {
                //Create an object of Document class
                Document document = new Document();
    
                //Load a Word document from disk
                document.LoadFromFile(@"D:\Samples\Sample.docx");
    
                //Insert an image watermark
                InsertImageWatermark(document);
    
                //Save the document
                document.SaveToFile("InsertImageWatermark.docx", FileFormat.Docx);
            }
            private static void InsertImageWatermark(Document document)
            {
                PictureWatermark picture = new PictureWatermark();
                picture.Picture = Image.FromFile(@"D:\Samples\Watermark.png");
                picture.Scaling = 200;
                picture.IsWashout = false;
                document.Watermark = picture;
            }
        }
    }

Imports System
    Imports System.Drawing
    Imports Spire.Doc
    Imports Spire.Doc.Documents
    
    Module Program
        Sub Main(args As String())
            'Create an object of Document class
            Dim document As New Document()
    
            'Load a Word document from disk
            document.LoadFromFile("D:\Samples\Sample.docx")
    
            'Insert an image watermark
            InsertImageWatermark(document)
    
            'Save the document
            document.SaveToFile("InsertImageWatermark.docx", FileFormat.Docx)
        End Sub
        Private Sub InsertImageWatermark(ByVal document As Document)
            Dim picture As New PictureWatermark()
            picture.Picture = Image.FromFile("D:\Samples\Watermark.png")
            picture.Scaling = 250
            picture.IsWashout = False
            document.Watermark = picture
        End Sub
    End Module