Document rtfFile = new Document(@"C:ToolsdocwithTextBox.rtf");
        DocumentBuilder builder = new DocumentBuilder(rtfFile);
        var nodes = rtfFile.GetChildNodes(NodeType.Shape, true);
        foreach (Shape shape in nodes)
        {

            if (shape.ShapeType == ShapeType.TextBox)
            {
                var width = shape.Width;
                var height = shape.Height;
                string text = shape.GetText();
                builder.MoveTo(shape);

                shape.Remove();

                Aspose.Words.Tables.Table table = builder.StartTable();
                Cell cell = builder.InsertCell();
                builder.Write(text);
                builder.RowFormat.Height = height;
                builder.RowFormat.HeightRule = HeightRule.Exactly;
                table.PreferredWidth = PreferredWidth.FromPoints(width);
                builder.EndRow();
                builder.EndTable();
            }
        }
        rtfFile.Save(@"C:ToolsdocwithTextBox.rtf");