WhatsApp is a popular messaging application that allows users to send text messages, voice messages, photos, videos, and documents to other WhatsApp users. It was founded in 2009 by Jan Koum and Brian Acton and was later acquired by Facebook in 2014.

WhatsApp uses end-to-end encryption, which means that messages and calls are only visible to the sender and receiver, and no one else, including WhatsApp itself. It also has features such as group chat, video calling, voice calling, and the ability to share your location.

In addition to personal messaging, WhatsApp is also used by businesses for communication with customers through the WhatsApp Business API. This enables businesses to send automated messages, provide customer support, and send updates to their customers.

WhatsApp is available for free on both Android and iOS devices, and can also be accessed through a web browser on a desktop computer.