Subscribe to an Email to SMS Account
Sign-up an account of Email to SMS service and purchase credit. Check the Email-to-SMS providers available in your country and choose the right SMS gateway provider to meet your needs.
Reference : https://email2sms.info/?
Manage allowed sender – Email-to-SMS provider only accepts the request from senders who listed in 'Allowed sender email addresses'.
Setup Notification Server
Configure mail server on gateway, Configuration → System → Notification → Mail Server.
Note: Because the gateway sends SMS messages to Email-to-SMS provider via email, the email notification capability needs to be configured.
Configure SMS service on gateway, Configuration → System → Notification → SMS.
User Account Setup
You need to configure user's phone number for two-factor authentication.
To make the necessary change(s) go to, Configuration → Object → User/Group → User.