Final answer:
The Themes gallery is accessed by clicking Themes in the Themes group on the PAGE LAYOUT tab in Microsoft Office applications.
Step-by-step explanation:
The Themes gallery is displayed by clicking Themes in the Themes group on the PAGE LAYOUT tab. When working with Microsoft Office programs such as Word, PowerPoint, and Excel, applying a theme can change the overall design of your document, including colors, fonts, and effects.
It's essential to know where to find these settings to efficiently utilize the available tools to improve the presentation of your work.