People use WhatsApp for a variety of reasons, including:

Messaging: WhatsApp is primarily used as a messaging app that allows users to send and receive text messages, voice messages, photos, videos, and documents to and from other WhatsApp users around the world.

Free: Unlike traditional SMS messaging, WhatsApp uses an internet connection to send messages, which means that users can avoid SMS fees and enjoy free messaging with other WhatsApp users.

Group Chat: WhatsApp also allows users to create and participate in group chats with up to 256 participants, making it easy to communicate with friends, family, and colleagues.

Voice and Video Calls: WhatsApp also offers voice and video call features, which are a convenient way to talk to someone over long distances without incurring long-distance charges.

Security: WhatsApp has end-to-end encryption, which means that messages and calls are secure and private.

Easy to Use: WhatsApp is easy to use and has a simple and intuitive interface, which makes it popular among users of all ages and technical abilities.

Overall, WhatsApp is a popular messaging app because it is free, easy to use, secure, and allows users to communicate with people all over the world using a single app.