an adverb describes an action or verb and provides an indication of when, where, how, or in what manner an action happened. Automatically functions as an adverb here to indicate that something happens without any input or assistance from a person, occurring in a mechanical or self-activated way.
I accidentally pressed the delete key and my document was automatically deleted.
The machine automatically resets itself after each cycle.
A situation will automatically activate the safety system.
though the word 'automatically' functions as an adverb in most cases, it does not always need to modify a verb. It can also modify an adjective or other adverb. For example, 'The process ran extremely automatically' or 'Our system is already automatically modified'.