C# .NET Document Editor SDK

//Get your App SID, App Key and Storage Name at https://dashboard.groupdocs.cloud (free registration is required).
var configuration = new Configuration(MyAppSid, MyAppKey);

// Create necessary API instances
var editApi = new EditApi(configuration );
var fileApi = new FileApi(configuration );

// The document already uploaded into the storage.
// Load it into editable state
var loadOptions = new WordProcessingLoadOptions
{
    FileInfo = new FileInfo
    {
        FilePath = "WordProcessing/password-protected.docx",
        Password = "password"
    },
    OutputPath = "output"
};
var loadResult = editApi.Load(new LoadRequest(loadOptions));

// Download html document
var stream = fileApi.DownloadFile(new DownloadFileRequest(loadResult.HtmlPath));
var htmlString = new StreamReader(stream, Encoding.UTF8).ReadToEnd();

// Edit something...
htmlString = htmlString.Replace("Sample test text", "Hello world");

// Upload html back to storage
fileApi.UploadFile(new UploadFileRequest(loadResult.HtmlPath,
    new MemoryStream(Encoding.UTF8.GetBytes(htmlString))));

// Save html back to docx
var saveOptions = new WordProcessingSaveOptions
{
    FileInfo = loadOptions.FileInfo,
    OutputPath = "output/edited.docx",
    HtmlPath = loadResult.HtmlPath,
    ResourcesPath = loadResult.ResourcesPath
};
var saveResult = editApi.Save(new SaveRequest(saveOptions));