The most reliable way is through the or Apple's official support links. Use the links below (best opened in Safari ): macOS Sequoia (15) macOS Sonoma (14) macOS Ventura (13) macOS Monterey (12)
Once downloaded, the installer (e.g., "Install macOS Sequoia") will appear in your folder. Step 2: Create the ISO via Terminal
: If you just need a bootable USB for a physical Mac, you do not need an ISO. Use the Apple Support Guide for the createinstallmedia command directly on a USB drive.