AddWatermarkToMultiframeImage.cs

TiffImageLoadOptions loadOptions = new TiffImageLoadOptions(); 
using (Watermarker watermarker = new Watermarker("sample.tiff", loadOptions))
{
	// Initialize text or image watermark
	TextWatermark watermark = new TextWatermark("Test watermark", new Font("Arial", 19));

	// Add watermark to a particular frame of image
	MultiframeImageWatermarkOptions options = new MultiframeImageWatermarkOptions();
	options.FrameIndex = 0;

	watermarker.Add(watermark, options);
	watermarker.Save("output.tiff");
}

AddWatermarkToPasswordProtectedDocument.cs

LoadOptions loadOptions = new LoadOptions();
loadOptions.Password = "P@$$w0rd";
string filePath = "sample.docx";
using (Watermarker watermarker = new Watermarker(filePath, loadOptions))
{
    // use watermarker methods to manage watermarks in the document
    TextWatermark watermark = new TextWatermark("Test watermark", new Font("Arial", 12));
 
    watermarker.Add(watermark);
 
    watermarker.Save("output.docx");
}