Marketing is the process of communicating value to prospects and guests. Marketing may take many different shapes, as is shown by the Marketing Mix. Various Toastmasters materials discuss Marketing. See, for example the District Leadership Handbook and the guide From Prospect to Guest to Member (item 108 at Toastmasters International Online Store).
While districts formerly had Lieutenant Governors of Marketing, nowadays the district-level position is called Club Growth Director. As for clubs, there is no Vice President of Marketing - the role is handled by the Vice President Membership.
Marketing may also be done through the sister club approach.