This is the 95th most frequent Ukrainian word.
всіх
"Всіх" means "everyone" or "all" in English.
Here, 'всіх' is used as the accusative plural form of the word 'всі' (all), agreeing with 'друзів' (friends), which is in the accusative plural as well.
Я знаю всіх твоїх друзів.
I know all your friends.
In this sentence, 'всіх' is employed as a pronoun in its accusative case plural to indicate all individuals in the room, carrying out the instruction.
Привітайте всіх у кімнаті!
Greet everyone in the room!
Here, 'всіх' signifies 'all' in the accusative plural case, connected with the object of 'отримають' (will be given).