Добавьте закладки в PDF в .NET SDK

    using Aspose.Pdf.Cloud.Sdk.Model;

    namespace Bookmarks
    {
        public class BookmarkAdd
        {
            public static async Task Append(string documentName, string outputName, string parentBookmarkPath, string title, string localFolder, string remoteFolder)
            {
		// Get your AppSid and AppSecret from https://dashboard.aspose.cloud (free registration required). 
		pdfApi = new PdfApi(AppSecret, AppSid);

                using (var file = File.OpenRead(Path.Combine(localFolder, documentName)))
		{ // Upload the local PDF to cloud storage folder name.
                    FilesUploadResult uploadResponse = await pdfApi.UploadFileAsync(Path.Combine(remoteFolder, documentName), documentName);
                    Console.WriteLine(uploadResponse.Uploaded[0]);
                }

                // Create new bookmark with input parameters for the PDF on cloud storage.
                Bookmark bookmark = new Bookmark(
                    Action: "GoTo",
                    Bold: true,
                    Italic: false,
                    Title: title,
                    PageDisplay: "XYZ",
                    PageDisplayBottom: 10,
                    PageDisplayLeft: 10,
                    PageDisplayRight: 10,
                    PageDisplayTop: 10,
                    PageDisplayZoom: 2,
                    PageNumber: 1,
                    Color: new Color(A: 0x00, R: 0x00, G: 0xFF, B: 0x00)
                );
                List<Bookmark> newBookmarks = new List<Bookmark>() { bookmark };

                // Append new bookmark under the parentBookmarkPath in the PDF on cloud storage.
                BookmarksResponse response = await pdfApi.PostBookmarkAsync(documentName, parentBookmarkPath, newBookmarks, folder: remoteFolder);

                // Checks the response and logs the result.
                if (response == null)
                    Console.WriteLine("BookmarkAdd(): Unexpected error!");
                else if (response.Code < 200 || response.Code > 299)
                    Console.WriteLine("BookmarkAdd(): Failed to append bookmark to the document.");
                else
                { // Downloads the updated file for local use.
                    Console.WriteLine("BookmarkAdd(): bookmark successfully appended to the document '{0}.", documentName);
                    Stream stream = pdfApi.DownloadFile(Path.Combine(remoteFolder, documentName));
                    using var fileStream = File.Create(Path.Combine(localFolder, "append_bookmark_" + outputName));
                    stream.Position = 0;
                    await stream.CopyToAsync(fileStream);
                    Console.WriteLine("BookmarkAdd(): File '{0}' successfully downloaded.", "append_bookmrk_" + outputName);
                }
            }
        }
    }