For Macs already running High Sierra or earlier, use this Terminal command:
macOS High Sierra 10.13.6 is a popular operating system for Mac computers, released on September 26, 2017. This update includes various security patches, bug fixes, and performance improvements. download macos high sierra 10.13 6 dmg file
For older versions that aren't easily found, the Apple Support legacy download page provides links that redirect your Mac to the correct App Store version. For Macs already running High Sierra or earlier,
macOS High Sierra (10.13.6) remains one of the most significant macOS releases, officially supporting the last generation of polycarbonate MacBooks and introducing the APFS file system to the masses. Whether you need to reinstall an older Mac, downgrade from a newer macOS version, or set up a virtual machine, obtaining the installation file can be tricky since Apple often hides older OS versions from the App Store. macOS High Sierra (10