This is the 4461st most frequent Russian word.
войдет
"Войдет" means "will enter" or "will come in" in English.
Here, 'войдет' is used to mean 'will enter', indicating a future action of entering a room.
Она войдет в комнату через минуту.
She will enter the room in a minute.
In this context, 'войдет' suggests 'will go down', metaphorically meaning to be remembered as part of history.
Этот эпизод войдет в историю.
This episode will go down in history.
Here, 'войди' is the imperative form of 'войдет', instructing someone to enter a place.