.NET PDF Library - Split PDF Files

//Add the required namespaces
using Syncfusion.Pdf.Parsing;
using Syncfusion.Pdf;

// Create the FileStream object to read the input PDF file
using (FileStream inputFileStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read))
{
    // Load the PDF document from the input stream
    using (PdfLoadedDocument loadedDocument = new PdfLoadedDocument(inputFileStream)) 
    {
        // Iterate over the pages of the loaded document
        for (int pageIndex = 0; pageIndex < loadedDocument.PageCount; pageIndex++) 
        {
            // Create a new PdfDocument object to hold the output
            using (PdfDocument outputDocument = new PdfDocument())
            {
                // Import the page from the loadedDocument to the outputDocument
                outputDocument.ImportPage(loadedDocument, pageIndex); 
                
                // Create the FileStream object to write the output PDF file
                using (FileStream outputFileStream = new FileStream($"Output{pageIndex}.pdf", FileMode.Create, FileAccess.Write))
                {
                    // Save the outputDocument into the outputFileStream
                    outputDocument.Save(outputFileStream);
                }
            }
        }
    }
}