“Everyone” means “everybody” and is used when you want to refer to all the people in a group: “Everyone in my family likes spaghetti carbonara.”
But if you’re referring to the individuals who make up a group, then the phrase is “every one.” Examples: “God bless us, every one” (may each individual in the group be blessed). “We wish each and every one of you a Merry Christmas” (every single one of you). In the phrase “each and every one” you should never substitute “everyone”).
For “everyone” as singular or plural, see “every.”