In PowerPoint, which feature is used to apply a background pattern to a slide?

Using a background pattern in PowerPoint is facilitated through the Pattern Fill feature. This function allows users to choose from various pre-defined patterns to enhance the visual appeal of slides. When selected, it enables customizable options, such as color choices for the foreground and background of the patterns, which helps in creating distinctive designs for presentations.

The other options do not specifically provide the functionality to apply a background pattern. Custom Backgrounds may refer to a broader approach to modifying slide backgrounds, Textures Fill usually pertains to integrating images or textured backgrounds rather than patterns, and Background Options may include a variety of settings for adjusting backgrounds but does not singularly focus on the application of pattern fills.

Therefore, the feature dedicated to applying a specific pattern to a slide is indeed the Pattern Fill, making it the correct choice in this context.