Apple provides a direct download link for macOS High Sierra on its website. Here's how:

The story of macOS High Sierra (10.13) is not one of flashy new buttons, but a radical "under-the-hood" reconstruction of the Mac's soul. Released on September 25, 2017, its name—suggesting a higher, more refined peak of the previous "Sierra" version—signaled its purpose as a technical polish, much like Snow Leopard before it. The Great File System Migration

If you need an ISO file for virtualization and you have the official App Store installer, you can convert it yourself. This is safer than downloading a random ISO from a forum.

The safest way to get High Sierra is directly from Apple. Third-party sites often host "distros" that may contain malware or unauthorized modifications.

The official method to obtain macOS High Sierra (10.13) is to download the installer via the Mac App Store in Safari, which can then be converted into a bootable ISO or DMG using Terminal commands. For creating USB installers or virtual machine files, specific hdiutil and createinstallmedia commands are used to convert the App Store application. For more details, visit Apple Support . How to download and install macOS - Apple Support (IN)

for systems already running an earlier version of High Sierra. Apple Support Third-Party ISO & DMG Mirrors

macOS High Sierra dmg download for making bootable usb insttaller