whatsapp otp required

I am looking to develop a system that requires user authentication using phone numbers, allowing them to access services via WhatsApp with one-time password (OTP) confirmation. The system needs to verify users' identity by asking them to provide their phone number before they can be granted access. I will be using the users' phone number as an authentication method requiring them to enter an OTP to verify the identity and grant them access. I do not need the system to track user activity.