Strategy management, as a general management practice in ITIL 4, is the practice of formulating the goals of an organization and adopting the courses of action and allocation of resources necessary for achieving those goals.
Strategy management is simply responsible for establishing the organization's direction, focusing efforts to finding and clarifying organizational priorities, and providing consistency or guidance in response to the environment. Normally, strategy management is going to be done at very high levels in your organization.
You're going to get direction from the CEO, as well as the other C-Suite executives, on which way the organization should be going. And they're going to do this based on the changing environment that they see outside of the organization. For example, look back at the early 2000s and think about the company called Kodak. Kodak was a traditional film company, and around the early 2000s, digital cameras, which no longer stored images in traditional films, were starting to outpace the way that traditional film companies were operating, because most people were moving from a regular camera to a digital camera.
Today in 2020, it would take a lot of effort to find someone who still uses a film camera. Come to think of it, only professionals or enthusiasts would still be using one. Looking at that trend, that would put Kodak out of business, because their major profit center was traditional film. What they really had to start doing was figuring out, with their strategy, should they pivot their business model? Should they move from film to digital cameras? They tried to do that, but they did so a little bit too late when newer companies had taken a bigger share of the camera market. Kodak didn't really get enough of a go, and that company ended up not doing well in the long-term. They didn't see the writing on the wall, they didn't react quick enough because their strategy didn't change quick enough.
Strategy management is focused on a quicker reaction. It's being able to see what the future is and turning the organization before that future hits you. That's the whole goal here - focusing your effort to find your organizational priorities and make sure that you're all aiming towards the same vision.