PM> Install-Package Spire.XLS

using Spire.Xls;

namespace LockCells
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Workbook instance
            Workbook workbook = new Workbook();
            //Load an Excel file
            workbook.LoadFromFile("Input.xlsx");

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

            //Unlock all cells in the used range of the worksheet
            CellRange usedRange = sheet.Range;            
            usedRange.Style.Locked = false;

            //Lock specific cells
            CellRange cells = sheet.Range["A1:C3"]; 
            cells.Style.Locked = true;

            //Protect the worksheet with password
            sheet.Protect("123456", SheetProtectionType.All);

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

Imports Spire.Xls

Namespace LockCells
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Workbook instance
            Dim workbook As Workbook = New Workbook()
            'Load an Excel file
            workbook.LoadFromFile("Input.xlsx")

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

            'Unlock all cells in the used range of the worksheet
            Dim usedRange As CellRange = sheet.Range
            usedRange.Style.Locked = False

            'Lock specific cells
            Dim cells As CellRange = sheet.Range("A1:C3")
            cells.Style.Locked = True

            'Protect the worksheet with password
            sheet.Protect("123456", SheetProtectionType.All)

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

PM> Install-Package Spire.PDF

using Spire.Pdf;

namespace SetViewerPreference
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Initialize an instance of PdfDocument class
            PdfDocument pdf = new PdfDocument();
            //Load a PDF document
            pdf.LoadFromFile(@"Example.pdf");

            //Get the PdfViewerPreferences object
            PdfViewerPreferences viewerPreferences = pdf.ViewerPreferences;

            //Set viewer preference           
            viewerPreferences.FitWindow = false;
            viewerPreferences.HideMenubar = true;
            viewerPreferences.HideToolbar = true;
            viewerPreferences.CenterWindow= true;
            viewerPreferences.DisplayTitle = false;
            viewerPreferences.PageLayout = PdfPageLayout.SinglePage;
            viewerPreferences.PageMode = PdfPageMode.UseNone;

            //Save the result document
            pdf.SaveToFile("SetViewerPreference.pdf");
            pdf.Close();
        }
    }
}

Imports Spire.Pdf

Namespace SetViewerPreference
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Initialize an instance of PdfDocument class
            Dim pdf As PdfDocument = New PdfDocument()
            'Load a PDF document
            pdf.LoadFromFile("Example.pdf")

            'Get the PdfViewerPreferences object
            Dim viewerPreferences As PdfViewerPreferences = pdf.ViewerPreferences

            'Set viewer preference           
            viewerPreferences.FitWindow = False
            viewerPreferences.HideMenubar = True
            viewerPreferences.HideToolbar = True
            viewerPreferences.CenterWindow = True
            viewerPreferences.DisplayTitle = False
            viewerPreferences.PageLayout = PdfPageLayout.SinglePage
            viewerPreferences.PageMode = PdfPageMode.UseNone

            'Save the result document
            pdf.SaveToFile("SetViewerPreference.pdf")
            pdf.Close()
        End Sub
    End Class
End Namespace

using Spire.Pdf;
using Spire.Pdf.Actions;
using Spire.Pdf.General;
using System.Drawing;

namespace SetZoomFactor
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Initialize an instance of the PdfDocument class
            PdfDocument pdf = new PdfDocument();
            //Load a PDF document
            pdf.LoadFromFile(@"Example.pdf");

            //Get the first page
            PdfPageBase page = pdf.Pages[0];

            //Initialize an instance of the PdfDestination class
            PdfDestination dest = new PdfDestination(page);
            //Set the destination mode
            dest.Mode = PdfDestinationMode.Location;
            //Set the destination location
            dest.Location = new PointF(40f, 40f);
            //Set the zoom factor
            dest.Zoom = 1.5f;

            //Initialize an instance of the PdfGoToAction class
            PdfGoToAction gotoAction = new PdfGoToAction(dest);
            //Set the action to be executed when the document is opened
            pdf.AfterOpenAction = gotoAction;

            //Save the result document
            pdf.SaveToFile("SetZoomFactor.pdf");
            pdf.Close();
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Actions
Imports Spire.Pdf.General
Imports System.Drawing

Namespace SetZoomFactor
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Initialize an instance of the PdfDocument class
            Dim pdf As PdfDocument = New PdfDocument()
            'Load a PDF document
            pdf.LoadFromFile("Example.pdf")

            'Get the first page
            Dim page As PdfPageBase = pdf.Pages(0)

            'Initialize an instance of the PdfDestination class
            Dim dest As PdfDestination = New PdfDestination(page)
            'Set the destination mode
            dest.Mode = PdfDestinationMode.Location
            'Set the destination location
            dest.Location = New PointF(40F, 40F)
            'Set the zoom factor
            dest.Zoom = 1.5F

            'Initialize an instance of the PdfGoToAction class
            Dim gotoAction As PdfGoToAction = New PdfGoToAction(dest)
            'Set the action to be executed when the document is opened
            pdf.AfterOpenAction = gotoAction

            'Save the result document
            pdf.SaveToFile("SetZoomFactor.pdf")
            pdf.Close()
        End Sub
    End Class
End Namespace