PM> Install-Package Spire.Doc

using Spire.Doc;

namespace BuiltinDocumentProperties
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Document instance
            Document document = new Document();
            //Load a Word document
            document.LoadFromFile("Sample.docx");

            //Add built-in document properties to the document
            BuiltinDocumentProperties standardProperties = document.BuiltinDocumentProperties;
            standardProperties.Title = "Add Document Properties";
            standardProperties.Subject = "C# Example";
            standardProperties.Author = "James";
            standardProperties.Company = "Eiceblue";
            standardProperties.Manager = "Michael";
            standardProperties.Category = "Document Manipulation";
            standardProperties.Keywords = "C#, Word, Document Properties";
            standardProperties.Comments = "This article shows how to add document properties";

            //Save the result document
            document.SaveToFile("StandardDocumentProperties.docx", FileFormat.Docx2013);
        }
    }
}

Imports Spire.Doc

Namespace BuiltinDocumentProperties
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Document instance
            Dim document As Document = New Document()
            'Load a Word document
            document.LoadFromFile("Sample.docx")

            'Add built-in document properties to the document
            Dim standardProperties As BuiltinDocumentProperties = document.BuiltinDocumentProperties
            standardProperties.Title = "Add Document Properties"
            standardProperties.Subject = "C# Example"
            standardProperties.Author = "James"
            standardProperties.Company = "Eiceblue"
            standardProperties.Manager = "Michael"
            standardProperties.Category = "Document Manipulation"
            standardProperties.Keywords = "C#, Word, Document Properties"
            standardProperties.Comments = "This article shows how to add document properties"

            'Save the result document
            document.SaveToFile("StandardDocumentProperties.docx", FileFormat.Docx2013)
        End Sub
    End Class
End Namespace

using Spire.Doc;
using System;

namespace CustomDocumentProperties
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Document instance
            Document document = new Document();
            //Load a Word document
            document.LoadFromFile("Sample.docx");

            //Add custom document properties to the document
            CustomDocumentProperties customProperties = document.CustomDocumentProperties;
            customProperties.Add("Document ID", 1);
            customProperties.Add("Authorized", true);
            customProperties.Add("Authorized By", "John Smith");
            customProperties.Add("Authorized Date", DateTime.Today);

            //Save the result document
            document.SaveToFile("CustomDocumentProperties.docx", FileFormat.Docx2013);
        }
    }
}

Imports Spire.Doc

Namespace CustomDocumentProperties
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Document instance
            Dim document As Document = New Document()
            'Load a Word document
            document.LoadFromFile("Sample.docx")

            'Add custom document properties to the document
            Dim customProperties As CustomDocumentProperties = document.CustomDocumentProperties
            customProperties.Add("Document ID", 1)
            customProperties.Add("Authorized", True)
            customProperties.Add("Authorized By", "John Smith")
            customProperties.Add("Authorized Date", Date.Today)

            'Save the result document
            document.SaveToFile("CustomDocumentProperties.docx", FileFormat.Docx2013)
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.XLS

using Spire.Xls;
using System.Drawing;

namespace ApplySuperscriptAndSubscript
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Create a Workbook object
            Workbook workbook = new Workbook();

            //Get the first worksheet
            Worksheet sheet = workbook.Worksheets[0];

            //Add text to specific cells
            sheet.Range["B2"].Text = "This is an example of subscript:";
            sheet.Range["D2"].Text = "This is an example of superscript:";

            //Add rich text to a specific cell
            CellRange range = sheet.Range["B3"];
            range.RichText.Text = "an = Sn - Sn-1";

            //Create a custom font
            ExcelFont font = workbook.CreateFont();
            //Enable the subscript property of the font
            font.IsSubscript = true;
            //Set font color
            font.Color = Color.Green;
            //Assign the font to specific characters of the rich text in the cell
            range.RichText.SetFont(6, 6, font);
            range.RichText.SetFont(11, 13, font);

            //Add rich text to a specific cell
            range = sheet.Range["D3"];
            range.RichText.Text = "a2 + b2 = c2";

            //Create a custom font
            font = workbook.CreateFont();
            //Enable the superscript property of the font
            font.IsSuperscript = true;
            //Assign the font to specific characters of the rich text in the cell
            range.RichText.SetFont(1, 1, font);
            range.RichText.SetFont(6, 6, font);
            range.RichText.SetFont(11, 11, font);

            //Auto-fit column widths
            sheet.AllocatedRange.AutoFitColumns();

            //Save the result file
            workbook.SaveToFile("ApplySubscriptAndSuperscript.xlsx", ExcelVersion.Version2013);
            workbook.Dispose();
        }
    }
}

Imports Spire.Xls
Imports System.Drawing

Namespace ApplySuperscriptAndSubscript
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Workbook object
            Dim workbook As Workbook = New Workbook()

            'Get the first worksheet.
            Dim sheet As Worksheet = workbook.Worksheets(0)

            'Add text to specific cells
            sheet.Range("B2").Text = "This is an example of subscript:"
            sheet.Range("D2").Text = "This is an example of superscript:"

            'Add rich text to a specific cell
            Dim range As CellRange = sheet.Range("B3")
            range.RichText.Text = "an = Sn - Sn-1"

            'Create a custom font
            Dim font As ExcelFont = workbook.CreateFont()
            'Enable the subscript property of the font
            font.IsSubscript = True
            'Set font color
            font.Color = Color.Green
            'Assign the font to specific characters of the rich text in the cell
            range.RichText.SetFont(6, 6, font)
            range.RichText.SetFont(11, 13, font)

            'Add rich text to a specific cell
            range = sheet.Range("D3")
            range.RichText.Text = "a2 + b2 = c2"

            'Create a custom font
            font = workbook.CreateFont()
            'Enable the superscript property of the font
            font.IsSuperscript = True
            'Assign the font to specific characters of the rich text in the cell
            range.RichText.SetFont(1, 1, font)
            range.RichText.SetFont(6, 6, font)
            range.RichText.SetFont(11, 11, font)

            'Auto-fit column widths
            sheet.AllocatedRange.AutoFitColumns()

            'Save the result file
            workbook.SaveToFile("ApplySubscriptAndSuperscript.xlsx", ExcelVersion.Version2013)
            workbook.Dispose()
        End Sub
    End Class
End Namespace