Add Text to the Headers of PDF documents via .NET SDK

    public static async Task AddTextHeader()
	{
	    const string localPdfDocument = @"C:\Samples\sample.pdf";
	    const string storageFileName = "sample.pdf";
	    const string headerText = "NEW TEXT HEADER";
	    const string localFolder = @"C:\Samples";
	    const string storageTempFolder = "YourTempFolder";
	    const string resultFileName = "output_add_text_header.pdf";
	    const int startPage = 2;
	    const int endPage = 5;

	    // Get your AppSid and AppSecret from https://dashboard.aspose.cloud (free registration required). 
	    var pdfApi = new PdfApi(AppSecret, AppSid);

	    using var file = File.OpenRead(localPdfDocument);
	    await pdfApi.UploadFileAsync(Path.Combine(storageTempFolder, storageFileName), file);

	    TextHeader footer = new TextHeader(
	        Background: true,
	        HorizontalAlignment: HorizontalAlignment.Center,
	        Opacity: 1,
	        Rotate: Rotation.None,
	        RotateAngle: 15,
	        XIndent: 0,
	        YIndent: 0,
	        Zoom: 1,
	        Value: headerText
	    );

	    var response = await pdfApi.PostDocumentTextHeaderAsync(storageFileName, footer, startPage, endPage, folder: storageTempFolder);

	    if (response == null)
	        Console.WriteLine("HeadersFootersAddTextHeader(): Unexpected error!");
	    else if (response.Code < 200 || response.Code > 299)
	        Console.WriteLine("HeadersFootersAddTextHeader(): Failed to append text header to the page of document.");
	    else
	    {
	        await (await pdfApi.DownloadFileAsync(Path.Combine(storageTempFolder, storageFileName)))
				.CopyToAsync(File.Create(Path.Combine(localFolder, resultFileName)));

	        Console.WriteLine("HeadersFootersAddTextFooter(): text '{0}' appended as header to the document '{1}.", headerText, resultFileName);
	    }
	}