At least 14.3GB of available space for the upgrade.
If you are on macOS Catalina or later, you can use the following command to download the full installer: softwareupdate --fetch-full-installer --full-installer-version 10.13.6 2. System Requirements Before installing, ensure your hardware is compatible: Memory: Minimum 2GB RAM (8GB recommended).
macOS High Sierra - Technical Specifications - Apple Support download+macos+high+sierra+10136+dmg+mac+install
For older Mac models, Apple hosts legacy installers. You can often download a disk image (.dmg) or package (.pkg) directly from Apple Support . Once downloaded, double-click the .dmg to find the .pkg file inside, then run it to place the "Install macOS High Sierra" app in your Applications folder.
