Returns a DocumentProtection object that can be used to get and set the protection settings that Word will apply to this document. (Only applicable to Word 2000 or above documents.)

 public DocumentProtection DocumentProtection{ get; }
Public ReadOnly Property DocumentProtection() As DocumentProtection

MS Word equivalent: Tools menu > Protect document... (plus some additional settings)

          DocumentProtection oDocumentProtection = oDocument.DocumentProtection;

          Dim oDocumentProtection As DocumentProtection = oDocument.DocumentProtection