Business process outsourcing (BPO) involves contracting non-core business functions like human resources, finance, and customer service to third-party service providers. There are three main types of BPO: offshore outsourcing uses providers in other countries, onshore outsourcing uses domestic providers, and nearshore outsourcing uses providers in neighboring countries. BPO provides advantages like reduced costs, focus on core business functions, and expertise from specialized providers, allowing companies to better meet changing customer demands. However, BPO roles can involve disadvantages like odd working hours, health issues from sedentary work, and social problems from long shifts.