Once you've downloaded the macOS High Sierra 10.13.6 DMG file, it's essential to verify its integrity to ensure it's not corrupted or tampered with. You can use tools like shasum or md5 to verify the checksum of the DMG file.

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyUSBDrive

Open Disk Utility , select the USB drive, and erase it using the Mac OS Extended (Journaled) format with a GUID Partition Map .