A person has 2 pens.
or
A person have 2 pens.
***** NOT A TEACHER *****
Bit,
(1) The moderator has already given you the answer.
(2) May I most respectfully remind you of the rule?
In the present tense, he/she/it takes an s in affirmative sentences:
A person ["she" or "he"] has two pens.
Every country ["it"] has a capital.
BUT you do not use the "s" in questions and the negative:
Does a person have a pen?
That country does not have a navy.