PM> Install-Package Spire.XLS

using Spire.Xls;
using System.Drawing;

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

            //Load a sample Excel file
            workbook.LoadFromFile("Test.xlsx");

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

            //Find all cells with the text "Regulator System"
            foreach (CellRange range in sheet.FindAllString("Regulator System", true, true))
            {
                //Set color to highlight the cells
                range.Style.Color = Color.Yellow;
            }

            //Save the result file
            workbook.SaveToFile("FindHighlight.xlsx", ExcelVersion.Version2016);
        }
    }
} 

Imports Spire.Xls

Namespace FindHighlight
    Class Program
        Private Shared Sub Main(ByVal args() As String)

            'Create a Workbook instance
            Dim workbook As Workbook = New Workbook

            'Load a sample Excel file
            workbook.LoadFromFile("Test.xlsx")

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

            'Find all cells with the text "Regulator System"
            For Each range As CellRange In sheet.FindAllString("Regulator System", True, True)

                'Set color to highlight the cells
                range.Style.Color = Color.Yellow
            Next

            'Save the result file
            workbook.SaveToFile("FindHighlight.xlsx", ExcelVersion.Version2016)
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.XLS

using Spire.Xls;
using System.Drawing;

namespace ReplaceDataInWorksheet
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Initialize an instance of the Workbook class
            Workbook workbook = new Workbook();
            //Load an Excel file
            workbook.LoadFromFile(@"Sample.xlsx");

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

            //Find the cells with the specific string value “Total” in the worksheet
            CellRange[] cells = worksheet.FindAllString("Total", true, true);

            //Iterate through the found cells
            foreach (CellRange cell in cells)
            {
                //Replace the value of the cell with another value
                cell.Text = "Sum";
                //Set a background color for the cell
                cell.Style.Color = Color.Yellow;
            }

            //Save the result file to a specific location
            workbook.SaveToFile("ReplaceDataInWorksheet.xlsx", ExcelVersion.Version2016);
            workbook.Dispose();
        }
    }
}

Imports Spire.Xls
Imports System.Drawing

Namespace ReplaceDataInWorksheet
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Initialize an instance of the Workbook class
            Dim workbook As Workbook = New Workbook()
            'Load an Excel file
            workbook.LoadFromFile("Sample.xlsx")

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

            'Find the cells with the specific string value “Total” in the worksheet
            Dim cells As CellRange() = worksheet.FindAllString("Total", True, True)

            'Iterate through the found cells
            For Each cell As CellRange In cells
                'Replace the value of the cell with another value
                cell.Text = "Sum"
                'Set a background color for the cell
                cell.Style.Color = Color.Yellow
            Next

            'Save the result file to a specific location
            workbook.SaveToFile("ReplaceDataInWorksheet.xlsx", ExcelVersion.Version2016)
            workbook.Dispose()
        End Sub
    End Class
End Namespace

using Spire.Xls;
using System.Drawing;

namespace ReplaceDataInCellRange
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Initialize an instance of the Workbook class
            Workbook workbook = new Workbook();
            //Load an Excel file
            workbook.LoadFromFile(@"Sample.xlsx");

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

            //Get a specific cell range
            CellRange range = worksheet.Range["A1:C9"];            

            //Find the cells with the specific value "Total" in the cell range
            CellRange[] cells = range.FindAllString("Total", true, true);

            //Iterate through the found cells
            foreach (CellRange cell in cells)
            {
                //Replace the value of the cell with another value
                cell.Text = "Sum";
                //Set a background color for the cell
                cell.Style.Color = Color.Yellow;
            }

            //Save the result file to a specific location
            workbook.SaveToFile("ReplaceDataInCellRange.xlsx", ExcelVersion.Version2016);
            workbook.Dispose();
        }
    }
}

Imports Spire.Xls
Imports System.Drawing

Namespace ReplaceDataInCellRange
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Initialize an instance of the Workbook class
            Dim workbook As Workbook = New Workbook()
            'Load an Excel file
            workbook.LoadFromFile("Sample.xlsx")

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

            'Get a specific cell range
            Dim range As CellRange = worksheet.Range("A1:C9")

            'Find the cells with the specific value "Total" in the cell range
            Dim cells As CellRange() = range.FindAllString("Total", True, True)

            'Iterate through the found cells
            For Each cell As CellRange In cells
                'Replace the value of the cell with another value
                cell.Text = "Sum"
                'Set a background color for the cell
                cell.Style.Color = Color.Yellow
            Next

            'Save the result file to a specific location
            workbook.SaveToFile("ReplaceDataInCellRange.xlsx", ExcelVersion.Version2016)
            workbook.Dispose()
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.XLS

using Spire.Xls;

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

            // Load an Excel file
            workbook.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.xlsx");

            // Get a specific worksheet
            Worksheet sheet = workbook.Worksheets[0];

            // Get the cell range (a single column) where you want to sort data
            CellRange cellRange = sheet.Range["F1:F6"];

            // Sort values in the specified column in descending order
            workbook.DataSorter.SortColumns.Add(5, SortComparsionType.Values, OrderBy.Descending);

            // Sort in the specified cell range
            workbook.DataSorter.Sort(cellRange);

            // Save the workbook
            workbook.SaveToFile("SortSingleColumn.xlsx", ExcelVersion.Version2013);

            // Dispose resources
            workbook.Dispose();
        }
    }
}

using Spire.Xls;

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

            // Load an Excel file
            workbook.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.xlsx");

            // Get a specific worksheet
            Worksheet sheet = workbook.Worksheets[0];

            // Get the cell range (multiple columns) where you want to sort data
            CellRange cellRange = sheet.Range["A1:F6"];

            // Sort values in the specified column in descending order
            workbook.DataSorter.SortColumns.Add(5, SortComparsionType.Values, OrderBy.Descending);

            // Sort in the specified cell range
            workbook.DataSorter.Sort(cellRange);

            // Save the workbook
            workbook.SaveToFile("SortMultipleColumns.xlsx", ExcelVersion.Version2013);

            // Dispose resources
            workbook.Dispose();
        }
    }
}

using Spire.Xls;

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

            // Load an Excel file
            workbook.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.xlsx");

            // Get a specific worksheet
            Worksheet sheet = workbook.Worksheets[0];

            // Get the cell range where you want to sort data
            CellRange cellRange = sheet.Range["A1:F6"];

            String[] customList = { "Central", "North", "South", "East", "West" };

            // Sort a specified column using the custom list
            workbook.DataSorter.SortColumns.Add(0, customList);

            // Sort in the specified cell range
            workbook.DataSorter.Sort(cellRange);

            // Save the workbook
            workbook.SaveToFile("SortByCustomList.xlsx", ExcelVersion.Version2013);

            // Dispose resources
            workbook.Dispose();
        }
    }
}