A business can only initiate a conversation outside of an active customer care window by using a template message. Template messages can only be sent using a predefined message template. Sending a template message begins a business-initiated conversation in one of three categories, each with a corresponding template type and pricing structure: utility, authentication, or marketing.
Sinch registers these message templates with WhatsApp for approval. Once the message template has been approved by WhatsApp, the client can dispatch them using the API.
Each message template can include personalization variables, which are defined in the onboarding worksheet. Sinch allows 250 such message templates to be created.
More information on WhatsApp template messages and the Conversation API
