MAPI provides other interfaces for creating containers in address books and adding recipients in the container. Messages, attachments, and other MAPI objects are principally composed of data called properties. A property is a data structure that contains a unique identifier, information about the data type, and the value of the data. Common MAPI properties include the subject line of a message, user names, and the body of an attachment. Properties are values read by the recipient or the transport that handles the delivery of the message.
Every property accessed by object methods has a unique name.
This returns a pointer to a message object. Message properties include the icon associated with the message, text that appears in the message's Subject field, and the text that makes up the body of the message. This saves all changes and marks the message for sending. At this point, the underlying messaging system takes over and delivers the message.