There are 3 different types of messages on WhatsApp:

1. Incoming Messages:

‍Any message that your customer sends you, is an incoming message. Every time you get an incoming message, WhatsApp gives you 24-hrs to respond to that customer message. This 24hr window is called the customer service window. 

2. Outgoing Messages:

Any message you send to the customers inside the 24-hr customer service window is an Outgoing message. Note, that the 24-hr window resets, each time your customer sends you a message. That is, you get a new 24-hr window to respond, every time a customer sends you a message.

3. Template Messages

To initiate a new conversation with a customer or reply to an incoming message outside the 24hr window, you’ll need to use a pre-approved template message.