Your marketing strategy will be your guide of the marketing efforts to be used to accomplish your business goals. Whether that's generate more leads, grow your email list, or increase sales on your website.
Your marketing strategy will utilize different marketing tactics such as email marketing, paid advertising, search engine optimization (SEO), remarketing as well as other tactics. The strategy will utilize the tactics to work together to achieve your goals.
The most important reason to have a marketing strategy is to really have a plan. Without a plan, you don't know where you're going or how to get there.