Automatically means by itself, with nobody having to act. The thing happens whether you remember or not.
It covers machines, so a door opens automatically, and rules, so a fine is applied automatically. That second use is where the word does most of its work in official writing, since automatic renewal and automatic enrolment mean you must act to stop them rather than to start them. There is a third sense about people, meaning without thinking, as in reaching automatically for the light switch.
1adverbautomaticallyBy itself, without human action.
“The lights switch off automatically at midnight.”
2adverbconsciousWithout conscious thought.
“She automatically reached for her phone.”
Proto-Indo-European
*men-
New Latin
automaticus
English
automatic
English, today
automatically
Built from
From automatic + -ally. automatic Borrowed from New Latin automaticus, from la-cla. New Latin automaticus, from la-cla automatum (“automaton”) + -icus, from Ancient Greek αὐτόματον, neuter of αὐτόματος (“self-moving, moving of oneself, self-acting, spontaneous”), from αὐτός (“self, myself”) + μέμαα (“to wish eagerly, strive, yearn, desire”). The original pronunciation, apparently with stress on the second syllable, was after the ultimate Greek base.
Etymology from Wiktionary, CC BY-SA