Anyone and Everyone have different meanings.

Everyone is all inclusive: “Everyone in the bar got drunk last night.” If I worded it “Anyone in the bar got drunk last night” – it doesn’t make sense.

Anyone refers to an amorphous, but not complete set. “Does anyone want to play checkers?” is much different from “Does everyone want to play checkers?” Anyone implies one or more, but not the whole group.

Anyone is singular, as is everyone. The first refers to any individual, the second is a whole collection that is making a singular reference.

The second part of those compound words, ”-one” indicates an individual. If you substitute it in your mind, it should make more sense.

Examples:

Although anyone (any individual) may attend, not everyone (every individual) will be there.

Both. “Anyone” can be one or all. “Everyone” is all.

Both “anyone” and “everyone” are generally treated as singular.

Test it yourself:

Everyone are going to the party.
Nope.

Everyone is going to the party.
There you go.

Think of each as a compound word. “Anyone” breaks down to “any one”, where one is the subject of the sentence, while “Everyone” breaks down “every one”, where one is the subject of the sentence.

And now, some American grammarians will come along and say that it’s not so simple, and both are accepted in some cases as non-singular because they are technically indefinite pronouns, but whatever. This works almost all of the time and is easy to remember.

As to the difference, that has been explained above. They’re comparable to the Boolean operators or and and. Anyone means “one of…” and everyone means “all of…”

Both are syntactically singular, but “everyone” is semantically plural and “anyone” can be semantically singular.

It’s the syntactic number that determines the agreement in the verb, so both words will take singular agreement.

This is a nice explanation

Anyone the word is any describe single person and the second one is also describe a single person. So this word anyone is single.