IPA: /ˈɔːtəfɪl/
KK: /ˈɔːtəfɪl/
A feature in software that automatically fills in information in forms or documents without needing the user to type everything out.
The autofill feature saved me time by completing my address in the online form.
Autofill is formed from "auto-" (from Greek "autos", meaning self) and "fill" (from Old English "fyllan", meaning to make full). The word describes a feature that automatically fills in information by itself.
Think of 'self' ('auto-') doing the action of 'filling' — that's why autofill means to fill in information automatically.
No commonly confused words.