Learn Hardcore Hebrew: זוזו פנימה, בבקשה.

זוזו is the imperative form of לזוז, which means to move, to budge, or to shift.
So here זוזו means move! when speaking to more than one person.

It is specifically the plural imperative.

Is זוזו for one person or for several people?

It is for several people.

In standard everyday use:

זוז = move! to one male
זוזי = move! to one female
זוזו = move! to more than one person

Important: Hebrew does not use the plural here as a polite singular the way some languages do. So זוזו really means you are addressing a group, not one person formally.

Why is there no word for you in the sentence?

Because in Hebrew, the imperative already includes the idea of you.

So זוזו already means you all move!
Adding אתם or אתן would usually sound unnecessary unless you wanted special emphasis.

This is normal in Hebrew, just like in English commands such as Come in! or Wait!, where you is also usually omitted.

Why does זוזו look like the same syllable repeated?