Once your business has completed the registration process, you will be able to send messages, even before WhatsApp verifies your business. Meta/WhatsApp refers to this as the Unverified trial experience and there are two levels:
Unverified trial experience (after registration is completed)
Notifications: You can send to up to 10 messages a day to two phone numbers. You can use preapproved message templates to send notifications.
Customer service messages: You can send messages to 10 phone numbers.
Extended trial experience (after the documents WhatsApp requests from you have been verified)
Notifications: You can send to up to 10 messages a day to two phone numbers. You can use preapproved message templates to send notifications.
Customer service messages: You can conduct up to 1500 client-initiated conversations. A conversation is a 24-hour messaging period with a specific phone number.