Merge two or more difference types of files into one file in C# using .NET API

MergeDifferentFiles.cs

// Combine two or more different types of files into one using C#
using (Merger merger = new Merger("document.pdf"))
{
    merger.Join("document.docx");
    merger.Join("spreadsheet.xlsx");
    merger.Save("merge_document.pdf");
}

MergeSelectivePages.cs

// Combine selective pages of two or more different types of files into one using C#
using (Merger merger = new Merger("document.pdf"))
{
    // Merge first page of DOCX file
    JoinOptions joinOptions = new JoinOptions(new int[] {1});
    merger.Join("document.docx", joinOptions);
    
    // Merge all the even pages/sheets of the spreadsheet from the provided range
    joinOptions = new JoinOptions(1,2, RangeMode.EvenPages);
    merger.Join("spreadsheet.xlsx", joinOptions);

    merger.Save("merge_document.pdf");
}