WhatsApp

• Business API number (Account → Channels → WhatsApp): tap Connect with Meta, or enter the phone number id, the WhatsApp Business Account id and a permanent access token yourself. Send a test confirms it. This is the route for ads, click-to-chat at volume, buttons, lists, link buttons and template receipts.
• Your own WhatsApp app (Account → Phone control → Bot on my WhatsApp): a bot answers the chats on this phone's WhatsApp or WhatsApp Business app. Nothing to host or verify; it works while the phone is on, and only for chats that raise a notification.
• A linked gateway: your normal WhatsApp number linked, like WhatsApp Web, to a small gateway on your machine. It can message anyone who has your number or has talked to you, read groups and start conversations. It is unofficial and carries a real ban risk if you message people who did not ask.

What a bot does in a chat

It reads the whole thread, understands photos, PDFs, voice notes and shared locations, sends your real files from the media library, shows buttons and menus on the Business API, books and reschedules with capacity checks, takes payments by link, writes to the CRM, and hands over when someone asks for a person, is upset, or asks for something outside its brief. Mark the bot Answer WhatsApp messages in its set-up to run it on every message to the connected number.

The 24-hour rule and templates

On the Business API a bot may reply freely for 24 hours after the person's last message. To start a conversation or follow up after that, it needs a template Meta has approved; the bot lists them with whatsapp_templates and uses them on its own. The phone and gateway routes have no templates and no window, which is exactly why they need restraint: only message people who gave you their number for this, and honour *stop* at once. Each plan allows a number of always-on channels: 1 on Free, 3 on Pro.

Every use case and every limit, route by route: WhatsApp automation: use cases and limitations.