Four categories
Marketing messages promote something: offers, launches, win-back campaigns. Utility messages are about something the customer already did: order confirmations, shipping updates, payment reminders. Authentication messages deliver one-time codes. Service messages are your replies inside the 24-hour window.
Why the category matters
Meta charges per message by category, and marketing costs the most. Meta decides the category from the template’s content, so a template written as an offer will be treated as marketing even if you submitted it as utility.
WhatsCommerce charges its own small fee by the same category and shows the price before you send. Service replies are free.
Choosing the right one
Write utility templates around a specific order or action, with the order number. Keep offers in marketing templates and only send them to people who opted in. For codes, use the authentication format.