The development of the advertising message that the marketer wants to convey to its target audience is called the

creative strategy

Explanation:

Creative strategy is part of advertising strategy, along with the media strategy used in the advertising campaign and refers to the development of the advertising message that marketers want to convey to their target audience. The great mission of creative strategy is the construction of the advertising message. This goes through two successive steps: and choosing the content of the message and the creative expression of it in a concrete message. Thus, there are different ways to work to find the most effective way to establish the content of the advertising message.