If you cannot find it in your Mac App Store purchases, search Apple’s official support article: – Apple still provides it for compatibility purposes.
Some notable features of macOS High Sierra include: macos.high.sierra.10.13.6.dmg
High Sierra introduced improved graphics processing capabilities, which helped bridge the gap for entry-level creative work on older machines. If you cannot find it in your Mac
Before downloading the DMG, ensure your hardware is compatible: macos.high.sierra.10.13.6.dmg
While many search for a direct "DMG" file, Apple primarily distributes the installer as an file via the App Store.