What is the DMG file format primarily used for?

The DMG file format is primarily used as a disk image file format for Apple macOS. This format allows users to create a compressed version of a disk or disk partition, which can be mounted as a virtual disk on a Mac. When a DMG file is opened, it appears as a new drive on the desktop, allowing users to access the contents inside, such as applications or files, just as they would with any physical storage device.

DMG files are particularly useful for distributing software, as they can package all the files necessary for installation while maintaining the organization and structure of the contents. Moreover, they can incorporate features like compression and encryption. This makes them a preferred choice for application developers and publishers on Apple's operating system.

In contrast, the other options do not accurately represent the primary function of the DMG format. For example, while audio files, data compression, and document storage are related to various other file formats, they do not encompass the specific use of DMG files in creating disk images on macOS.