Definition - What does Autofill mean?
Autofill is a function in some computer applications typically containing forms, most notably web browsers, which fills in the fields automatically according to the information that the user has previously used. This works on most common forms for fields such as names, addresses, telephone numbers and email addresses, which saves the user time compared to manually having to type the same information every time a different website asks for it.
Techopedia explains Autofill
Autofill is a function commonly found in web browsers such as Chrome, Opera and Firefox, where the browser remembers the common information input by the user, and later uses it to automatically fill in the fields which require that same information, possibly on a different website.
Most websites, when asking for user information, often ask for the name on the topmost and first fields, so when the user types in their name, the browser remembers all the information associated with this specific information and then fills out the other fields with the associated information. Autofill should not be confused with the autocomplete function, since that only works for the current field in focus.