PM> Install-Package Spire.Doc

using Spire.Doc;
using Spire.Doc.Documents;
using Spire.Doc.Fields;

namespace MultiLineTextWatermark
{
    class Program
    {
        static void Main(string[] args)
        {
            //加载Word文档
            Document doc = new Document();
            doc.LoadFromFile("http://cdn.e-iceblue.cn/Sample.docx");

            //创建形状，并设置大小、文本内容、位置及样式
            ShapeObject shape = new ShapeObject(doc, ShapeType.TextPlainText);
            shape.Width = 60;
            shape.Height =15;
            shape.VerticalPosition = 25;
            shape.HorizontalPosition = 20;
            shape.Rotation = 320;
            shape.WordArt.Text = "内部使用";
            shape.WordArt.FontFamily = "宋体";
            shape.FillColor = System.Drawing.Color.Red;
            shape.StrokeColor = System.Drawing.Color.Red;

            //遍历所有section
            for (int n = 0; n < doc.Sections.Count; n++)
            {
                Section section = doc.Sections[n];

                //获取页眉
                HeaderFooter header = section.HeadersFooters.Header;
                
                //添加段落到页眉
                Paragraph paragraph1 = header.AddParagraph();

                for (int i = 0; i < 5; i++)
                {
                    
                    for (int j = 0; j < 6; j++)
                    {
                        //复制形状并设置多行多列位置
                        shape = (ShapeObject)shape.Clone();
                        shape.VerticalPosition = 50 + 150 * i;
                        shape.HorizontalPosition = 20 + 160 * j;
                        
                        //添加形状到段落
                        paragraph1.ChildObjects.Add(shape);
                    }
                }
            }

            //保存文档
            doc.SaveToFile("result.docx", FileFormat.Docx2013);
        }
    }
}

Imports Spire.Doc
Imports Spire.Doc.Documents
Imports Spire.Doc.Fields

Namespace MultiLineTextWatermark
	Class Program
		Private Shared Sub Main(args As String())
			'加载Word文档 Dim doc As New Document() doc.LoadFromFile("http://cdn.e-iceblue.cn/Sample.docx") '创建形状，并设置大小、文本内容、位置及样式
			Dim shape As New ShapeObject(doc, ShapeType.TextPlainText)
			shape.Width = 60
			shape.Height = 15
			shape.VerticalPosition = 25
			shape.HorizontalPosition = 20
			shape.Rotation = 320
			shape.WordArt.Text = "内部使用"
			shape.WordArt.FontFamily = "宋体"
			shape.FillColor = System.Drawing.Color.Red
			shape.StrokeColor = System.Drawing.Color.Red

			'遍历所有section For n As Integer = 0 To doc.Sections.Count - 1 Dim section As Section = doc.Sections(n) '获取页眉
				Dim header As HeaderFooter = section.HeadersFooters.Header

				'添加段落到页眉 Dim paragraph1 As Paragraph = header.AddParagraph() For i As Integer = 0 To 4 For j As Integer = 0 To 5 '复制形状并设置多行多列位置
						shape = DirectCast(shape.Clone(), ShapeObject)
						shape.VerticalPosition = 50 + 150 * i
						shape.HorizontalPosition = 20 + 160 * j

						'添加形状到段落 paragraph1.ChildObjects.Add(shape) Next Next Next '保存文档
			doc.SaveToFile("result.docx", FileFormat.Docx2013)
		End Sub
	End Class
End Namespace