LockWatermarkInWordDocument.cs

WordProcessingLoadOptions loadOptions = new WordProcessingLoadOptions();
using (Watermarker watermarker = new Watermarker("document.docx", loadOptions))
{
    TextWatermark watermark = new TextWatermark("Watermark text", new Font("Arial", 19));
    watermark.ForegroundColor = Color.Red;
 
    WordProcessingWatermarkPagesOptions options = new WordProcessingWatermarkPagesOptions();
    options.IsLocked = true;
    options.LockType = WordProcessingLockType.AllowOnlyComments;
    /* 
    options.LockType = WordProcessingLockType.AllowOnlyRevisions;
    options.LockType = WordProcessingLockType.AllowOnlyFormFields;
    options.LockType = WordProcessingLockType.ReadOnlyWithEditableContent;
    options.LockType = WordProcessingLockType.ReadOnly; 
    */
 
    // To protect with password
    //options.Password = "7654321";
 
    watermarker.Add(watermark, options);
    watermarker.Save("document_watermarked.docx");
}