* "Person" as a general term: You would use the sign for "human" (the sign looks like you're making a fist and then opening your hand to show the fingers).
* "Person" referring to a specific individual: You can use the sign for "he/she/they" and then point to the person you're referring to.
* "Person" describing someone's occupation: You can use the sign for "worker" or "employee".
It's important to understand the context of the conversation to know how to best sign "person."
If you're looking to learn more about sign language, consider finding a local ASL class or using online resources like Handspeak.com.