📄️ 1. Can we use phone number that has been registered with Whatsapp Business before?
To apply for WhatsApp API Verification, you must use a phone number that is not currently associated with any WhatsApp accounts or applications.
📄️ 2. How should I choose a phone number for WhatsApp API Number?
You must use a valid phone number and must include a country and area code. The phone number must be able to receive calls or SMS for account verification.