Messages Meta approves in advance, for starting a conversation or writing after 24 hours.
Templates are messages Meta approves in advance. You need one to start a conversation, or to write to someone more than 24 hours after their last message.
Open Templates in the sidebar and press Create from library (or Create from scratch).
Press Use next to the wording you want.
Check the name and text. Names use lowercase letters, numbers and underscores. Meta may reclassify the category you pick.
Press Submit to Meta. The status moves from Submitting to Pending to Approved or Rejected by itself. You don't need to refresh.
Utility or Marketing? Utility is for messages about an order, booking, payment or account. Marketing is for promotion, such as a follow-up asking whether someone wants more details.
Text can't start or end with a variable such as {{3}}. The form stops you and says so. Press Sync with WhatsApp to pull in templates you created in WhatsApp Manager.