WhatsApp is a free messaging application owned by Meta that allows users to send text messages, make voice and video calls, share images, videos, documents, and conduct business communication. It supports end-to-end encryption and is available on Android, iOS, and desktop. WhatsApp Business offers automated replies, catalog management, and broadcast features for SMEs. It's widely used globally for personal, professional, and customer support conversations due to its simplicity and real-time connectivity.