Apple officially supports macOS High Sierra (10.13.6) only through the App Store’s “Purchased” tab or via direct links on their support site. However, a quick Google search reveals countless links to Google Drive, Dropbox, and random file-hosting sites promising the final .dmg (Disk Image) of 10.13.6. Here is my experience evaluating that ecosystem.
macOS High Sierra Full Installer Download Link (January 2024) --- Macos High Sierra 10.13.6 Dmg Google Drive