Given a reference text about Puerto Rico, tell me if it is a State, are its resident US citizens, and if they pay US taxes.

No, Puerto Rico is not a US state. Rather, it is a US territory. Puerto Rican citizens have automatic US citizenship. Due to this, residents of Puerto Rico and the United States can travel freely between the two, without passports. Puerto Rican residents do not pay federal income tax nor do they vote for the US president.