A marketing strategy is a plan of action designed to promote and sell a product or service. According to Investopedia
A marketing strategy is a business’s overall game plan for reaching people and turning them into customers of the product or service that the business provides. The marketing strategy of a company contains the company’s value proposition, key marketing messages, information on the target customer and other high-level elements.
The marketing strategy informs the marketing plan, which is a document that lays out the types and timing of marketing activities. A company’s marketing strategy should have a longer lifespan than any individual marketing plan as the strategy is where the value proposition and the key elements of a company’s brand reside. These things ideally do not shift very much over time.