DMG files are containers for apps in macOS. You open them, drag the app to your Applications folder, and then eject them, saving you the hassle of the dreaded "Install Wizard" of most Windows apps.
A DMG file stands for Disk Image File. Any file with the extension of ".dmg" is an Apple Disk Image File. This image format is commonly used by macOS operating system. It is also referred to as a macOS X Disk Image file that is a digital reconstruction of a physical disc.
A DMG file is an Apple Disk Image file often used to store compressed software installers. You can open DMG files on Windows, Mac, and Linux.