To change the background style of a presentation, you should:

The most effective way to change the background style of a presentation is by accessing the Design tab and selecting from the Background Styles options. This approach allows you to apply a consistent background to all slides quickly and efficiently, enhancing the overall aesthetics of the presentation.

Using the Design tab enables you to view a variety of predefined background styles and themes, making it easier to select an option that aligns with your presentation's content and intent. This method streamlines the process, as changes made here can be uniformly applied to all slides or specific ones by selecting options accordingly.

While other methods mentioned might provide ways to alter backgrounds, they are less efficient. For instance, formatting each slide individually for background could lead to inconsistencies and would require more time and effort, especially in larger presentations. Selecting Background Options via a right-click could change specific backgrounds but lacks the comprehensive selection and design coherence found in the Design tab. Thus, choosing Background Styles from the Design tab is the most practical and visually cohesive choice.