Each chat you see on your WhatsApp app has its own unique identifier.
These are private chat, group chat and WhatsApp channel.
Private chat is used to send personalized messages to the recipient. Group chat is used to organize communication between several participants in one group. Channel is used for unidirectional broadcasting tool where administrators can send text, photos, videos.
Before sending a message to these chats, a chat ID is required.
You will get the chat_id in the response to requests (like Get messages) and in Webhooks.
Private chat or correspondent identifier
The format of the private chat identifier is based on the template [email protected], where the recipient's phone number is used instead of the zeros. The phone number should be specified in full, with the country code and without spaces and without a plus. For example: [email protected]