Interestingly, this question is backwards, because a strategy's objectives should be defined before a strategy is devised. A strategy is a communicable plan to maximize and sustain the most important outcomes—so it is drive by the outcomes (aka objectives, aka KPI targets). If there's no outcome in mind, a strategy can't be created for achieving it. Try taking a taxi without telling the driver the destination.
The true answer to this question, therefore, is this: the desired KPIs should be determined at the start of the strategy planning process, and the strategic initiatives should be the mechanism by which to achieve those KPIs. This has a huge side-effect—the KPIs are very obvious, and very easy to measure.
For some examples of Strategic Statements that have the KPIs embedded into them, check out this FAQ question: What are some examples of strategy plans? And to learn more about KPIs in general, check out our article on how to create effective KPIs.
Outcomes are the highest-level measures of success of an organization, and are primarily quantitative (eg "Reach $10M in runrate revenue" or "House 50,000 homeless").
These outcomes are subjective, which can make them tricky to set, but they are defined according to shareholder/stakeholder needs and priorities, as well as the mission.
Outcomes are the anchor of strategy; they should be concrete, unarguable, and rarely change. To avoid conflation with performance, outcomes have a time horizon (eg 2-5 years) instead of strict timelines (eg by December 2023).
For more information, read more about how outcomes form starting point of any strategy.