Note: macOS High Sierra (10.13.6) is an older Apple release. If you need it for compatibility with legacy hardware or software, use Apple’s official sources when possible and verify file integrity. Installing or running older macOS versions can expose you to security vulnerabilities; consider using a VM or isolated machine.
Community-uploaded macOS 10.13.6 DMG is often used for legacy support. System Requirements for macOS 10.13.6 download macos high sierra 1013 6 dmg file link
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/install_build Downloading macOS High Sierra 10