download MS Word into my Mac 10.12.6

Microsoft doesn’t support macOS that far back, and doesn’t (openly) offer old downloads, either.

You can get to at least macOS 10.13, and potentially newer depending on the particular Mac model and year. That upgrade would make this quest slightly less effort.

LibreOffice 7.4.7.2 should work on macOS 10.13, as an alternative. That’s at least available for download.

Microsoft Word requires macOS Ventura 13 or later.