Agrega los componentes MAPISession y MAPIMessages
Private Sub CmdSend_Click()
MAPISession1.SignOn
MAPIMessages1.SessionID = -1
MAPIMessages1.Compose
MAPIMessages1.RecipAddress =
mail@server.com 'Capturalo con Text O Input
MAPIMessages1.MsgSubject = "Asunto"
MAPIMessages1.MsgNoteText = "Mensaje"
MAPIMessages1.MsgReceiptRequested = True
MAPIMessages1.Send False
MAPISession1.SignOff
End Sub