Everyone means every person; It can be replaced with everybody if used correctly. Let's go everyone! Everyone had tried the soup, they thought it was delicious. Every one means every item or each item in a set of things, or people; every can be replaced with each when it is being used correctly. John drew his bow, and fired arrows at all the targets, hitting every one of them. The success of this company is because of the work of every one of you.

How come this question appears in the French section?? By the way, in French, I would say : - "every one" : chacun(e), chaque - "everyone" : tous, tout le monde