In order for you (the business) to send messages outside of a customer care session, you must use an approved template. If the template is to be used to send promotional messages, select the Alert Update category when creating the template. Also, make sure the content of your message conforms to the WhatsApp Commerce Policy.
Note: When communicating with an end-user during a customer care session, you can send promotional content without using an approved template.
Learn more about the Sinch WhatsApp Business API.