The Fascinating History of Autocorrect (2014)

As Hachamovitch saw it, the main thing that people do on a word processor is type—and typing, in his estimation, is a matter of “a little bit of creativity and a whole lot of scutwork.” The notion of autocorrect was born when Hachamovitch began thinking about a functionality that already existed in Word. The resulting list ran to hundreds of entries:
anally, asshole, battle-axe, battleaxe, bimbo, booger, boogers, butthead, Butthead …
With these sorts of master lists in place—the corrections, the exceptions, and the to-be-primly-ignored—the joists of autocorrect, then still a subdomain of spell-check, were in place for the early releases of Word.

Source: www.wired.com