Everything worth knowing, nothing that isn't.
Why templates exist
WhatsApp is permission-based: outside the 24-hour window opened by a customer's message, you can only reach them with a template Meta has approved. This protects users from spam and keeps business messaging useful. See /answers/whatsapp-24-hour-window.
The three categories
Utility (transactional updates like orders and appointments), Authentication (one-time passcodes), and Marketing (promotions and offers). Category affects approval rules and the per-message price, so pick the right one. See /answers/what-is-conversation-pricing-whatsapp.
Getting a template approved
Submit through your BSP with clear, policy-compliant content and correctly declared variables. Vague, promotional-in-disguise, or policy-violating templates get rejected. See /answers/what-is-whatsapp-bsp and /answers/what-is-whatsapp-business-api.
Design for reuse
Use variables for names, codes, and order numbers so one approved template serves many messages, and add quick-reply or call-to-action buttons to drive the next step. See /answers/whatsapp-for-customer-support.