Microsoft give very little away and Word definitely isn't among them. (Some computers are sold with 'starter' editions of Microsoft Office, including just Word and Excel, but they're not made available for download).
If you want a freebie you'll probably have to download any one of the three big office suites (OpenOffice, Libre Office, WPS Office Free).
There are a few alternatives available but (unless you never share documents with others) you'd need to check whether they can handle Microsoft formats. See here for details:
https://www.thebalance.com/free-word-processors-1356338
(NB: Although that page is only a few months old, some things are already out of date. Kingsoft Office is now renamed to WPS Office and AbiWord is now no longer available for Windows).