UX Strategy, short for User Experience Strategy, involves taking a big picture view of how the usability of your product can help you achieve your business goals.
To create a UX Strategy, you must engage in research and design with your users in mind. You need to explore how the people who use your product are actually interacting with it to achieve their goals (or discovering why they're not). Then you can take what you learn from research and testing to improve the usability of your product.
Creating a User Experience Strategy is the first step toward making sure your product is designed so users can easily achieve their goals.