By default, when the user enters a phone number, we'll send a verification code or magic link using SMS. You can add the option for your users to receive the verification code or link as a WhatsApp message.
How to Add the WhatsApp Option
In your dashboard > Branding, select the WhatsApp checkbox for the Magic Link Form tab and OTP Verification Tab.
Enabling WhatsApp to send a verification code
WhatsApp Opt-In Requirements
WhatsApp requires that your application implement explicit user opt-ins to deliver messages over WhatsApp.