We use person in the singular to refer to any human being:
Joel is such a nice person.
She’s a person I have a lot of respect for.
Persons (plural) is a very formal word. We only use it in rather legalistic contexts:
[notice in a lift]
Any person or persons found in possession of illegal substances will be prosecuted.
To refer to groups of human beings or humans in general, we use people:
I saw three people standing on the corner.
Not: I saw three persons …
Jim and Wendy are such nice people.
People are generally very selfish.
Three people were interviewed for the job, but only one person had the right qualifications and experience.
