As a general rule, you're absolutely right – person is used to refer to an individual, and the plural form is people.

Can you say 2 persons?

Generally, persons is a decent substitute for individuals, and appears more in legal contexts that demand precision. People is the ordinary plural of person. Asking for a table for two or a table for two people is better than asking for a table for two persons.

Can you add S on person?

With verbs, only those with a third-person singular noun or pronoun (he, she, boat, courage) as a subject add an s to the end. Verbs with plural nouns and pronouns do not add s at the end. ... We would say “the people talk,” and people is a plural noun, so talk (no s) is a plural verb.