The different Message Types
Message Templates vs. Chat Messages
To initiate a conversation as a business you’ll need to setup so-called Message Templates. If a user initiates the conversation, or replies to a templated message, a ’24-hour support window’ starts, where you can reply to the user freely without a templated message.
Business Initiated Conversations
When you initiate a conversation with your users, you will need to use Message Templates. These templates must be pre-approved by WhatsApp. With Message Templates you can send notifications, updates, reminders, and more. In addition to text, images and PDFs are available as media message templates.
User Initiated Conversations
When a user sends a message to your WhatsApp Business Account (starting the 24-hour support window) you can send messages to that user without the use of a templated message. For Chat messages, there are no WhatsApp fees.