This is the most critical step. You cannot send messages to users who have not explicitly agreed to receive communications from your business on WhatsApp.
Methods of Opt-in:
Website Forms: A clear checkbox on your website signup forms (e.g., "Receive updates via WhatsApp").
Click-to-WhatsApp Ads: Users click an ad (on Facebook/Instagram) that opens a chat with your business. While this initiates a conversation, you should still explicitly ask for consent for future marketing/promotional messages within the chat.
QR Codes: Users scan a QR code (in-store, on packaging, flyers) that pre-fills a message. Their sending of this message indicates consent for that initial interaction.
In-App/In-Service Opt-in: Within your app or service, offer an option to receive notifications via WhatsApp.
Customer Service Initiated: If a customer contacts you, you can offer them to opt-in for future updates or specific message types.
Record Keeping: Keep detailed whatsapp number list records of when and how each user opted in.
II. Message Types and Templates (Post-July 1, 2025 Pricing Changes)
Starting July 1, 2025, WhatsApp's pricing for business-initiated messages is moving to a per-message model based on category, with volume-based discounts. This makes message categorization and template approval even more critical.
Marketing Templates: For promotional content, offers, announcements, re-engagement campaigns. These are generally the most expensive per message.
Utility Templates: For transactional messages specific to a user's transaction, account, or security (e.g., order confirmations, shipping updates, payment reminders, account alerts). These are typically cheaper and free if sent within a 24-hour customer service window after user-initiated contact.