You can find the macOS High Sierra page in the App Store. Note that searching for it directly may not work if your Mac is running a newer OS; you must use a direct link to trigger the "Get" button.
macOS High Sierra 10.13.6 full installer - Apple Communities mac os x 1013 high sierra dmg download hot
macOS High Sierra 10.13.6 Combo Update (recommended for updating from any version of 10.13). macOS High Sierra 10.13.6 Update . You can find the macOS High Sierra page in the App Store
Apple provides "Combo" and standard updates for specific versions: mac os x 1013 high sierra dmg download hot
Depending on your current system, use one of the following official channels:
Use Disk Utility to format a drive (at least 16GB) as Mac OS Extended (Journaled) .