Twilio UI configuration
Create a Twilio subaccount
Navigate to Account and select Subaccounts.
Click Create Subaccount.
Provide Friendly Name for new subaccount.
Click Create subaccount.
Click on the newly created subaccount.
On the left side of the screen, navigate to # Phone Number > Manage > Verified Caller IDs.
An existing non-Twilio phone number, like the number to a wireless phone or a landline in your home or office, must be validated on your Twilio account, via a One-time-passcode (OTP), before it can be used for specific Twilio account services.
On the left side of the screen, navigate to # Phone Number > Manage > Buy a number.
Click Buy on the preferred number.