: If you are already on macOS Catalina or later, you can use the softwareupdate command: softwareupdate --fetch-full-installer --full-installer-version 10.12.6 . Installation Steps from a DMG
Go to your Applications folder and look for Install macOS Sierra . 3. Creating a Bootable USB (Optional) Download Mac Os Sierra 10.12 Dmg
To install Mac OS Sierra 10.12 from the DMG file: : If you are already on macOS Catalina
MacBook Air, MacBook Pro, Mac mini, or Mac Pro (2010 or newer) Download Mac Os Sierra 10.12 Dmg
Downloading the macOS Sierra 10.12 DMG is primarily done for upgrading older hardware or creating bootable installation media. While macOS Sierra is no longer officially supported with security updates, Apple still provides the disk image for users with compatible older Macs. Where to Download macOS Sierra 10.12