Microsoft WORD for MAC OS 10.13

Unless you have Word (Office 2011 for Mac) backed up on Time Machine from that same Mac mini's hard drive where it was originally installed, you cannot get Word for macOS High Sierra. Microsoft has retired all prior Office versions except the current Microsoft 365, Office 2019 for Mac, and Office 2021 for Mac. They also disabled the license servers for their retired products, and any new installation (currently) older than macOS Catalina or later will be blocked. Once Ventura is released, in very short order, Microsoft will make macOS Big Sur the minimum Office installation platform.

Softmaker's Office 2021 suite of applications is still supported on High Sierra and it has the modern Word interface and native document compatibility. There is a trial on their site. Then there is the free LibreOffice Suite which in March 2023, will no longer support High Sierra for new releases and require Mojave at that time. LibreOffice has detailed user guide PDFs, though you can still expect a learning curve.