WhatsApp is a free, cross‑platform messaging app that lets people send text messages, voice messages, photos, videos, documents, and locations, as well as make voice and video calls, all over an internet connection. It’s widely used worldwide and is owned by Meta Platforms (the same company behind Facebook and Instagram). Messages are sent securely using end‑to‑end encryption, meaning only the sender and recipient can read them. How it works in brief

• Registration: You sign up with your phone number. The app uses that number as your unique identifier, and you verify it via a code sent by SMS.
• Internet-based communication: WhatsApp relies on an active internet connection (Wi‑Fi or mobile data) rather than traditional SMS/MMS. This makes it free to use wherever there’s internet access.
• Contacts and matching: WhatsApp automatically detects which of your phone’s contacts are also using the app, so you can start chats without asking others to install or share usernames.
• Messages and media: You can send text, voice messages, photos, videos, documents, voice calls, and video calls. You can also create group chats with multiple participants.
• Security: Messages and calls are protected by end‑to‑end encryption by default, helping keep conversations private between participants.
• Availability: It’s available on mobile devices (iOS and Android) and can be used on desktop or web browsers by linking to the mobile app.

Common uses and features

• Personal communication: One‑to‑one chats, voice/video calls, and group conversations with family and friends.
• Media sharing: Easy sending of photos, videos, voice messages, and documents.
• Status updates: Temporary posts (similar to a social feed) that disappear after 24 hours.
• Business use: WhatsApp Business adds tools for businesses to communicate with customers, including quick replies and automated messages.

If you’d like, I can tailor this to your needs—e.g., how to install and sign up, privacy settings to adjust, or tips for using specific features like group chats, disappearing messages, or WhatsApp Business.