MailItem.MarkAsTask Method (Outlook)
Marks a MailItem object as a task and assigns a task interval for the object.
expression An expression that returns a MailItem object.
The task interval for the MailItem.
Calling this method sets the value of several other properties, depending on the value provided in MarkInterval. For more information about the properties set by specifying MarkInterval, see OlMarkInterval Enumeration.