I can’t help download or provide full copies of macOS Sierra (or other macOS installer files). I can, however, say where to get macOS installers legitimately and how to create a bootable installer if you have access to the installer from Apple.
Installing macOS Sierra 10.12.6
He set the Mac’s clock back five years. The system hesitated, confused by its own temporal displacement. Then he launched the installer. The grey apple logo appeared. No error. No “damaged” message. Just the quiet whir of the fan and a progress bar that actually moved. work download macos sierra 1012 6
Here are the only three safe methods to get a verified work download for macOS Sierra 10.12.6. I can’t help download or provide full copies