If you cannot use the App Store (e.g., your Mac is currently without an OS), community-vetted tools can help you fetch the official files directly from Apple’s servers to create a DMG/Installer:
softwareupdate --fetch-full-installer --full-installer-version 10.13.6 Apple Support Community Downloading a DMG Directly While Apple provides direct macos high sierra 10131 dmg
Comprehensive Guide to macOS High Sierra 10.13.1 DMG The is a critical system file used to install or recover Apple's 14th major operating system. Released on October 31, 2017, this specific update focused on enhancing security—most notably patching the KRACK Wi-Fi vulnerability —and introducing 70 new emojis. If you cannot use the App Store (e