MsoEnvelope interface

Provides access to functionality that lets you send documents as emails directly from Microsoft Office applications.

Namespace:  Microsoft.Office.Core
Assembly:  office (in office.dll)

public interface MsoEnvelope : IMsoEnvelopeVB, 

Use the MailEnvelope property of the Document object, Chart object or Worksheet object (depending on the application you are using) to return an MsoEnvelope object.