How do I add a verified outgoing caller ID with Twilio?
To verify new outgoing caller ID numbers, you can either use the account dashboard or the REST API. To use your dashboard, log into your Twilio account and visit the Phone Numbers tab. Click the Verify a number button at the top of the page. To use the REST API, POST your phone number to the Outgoing Caller IDs list resource.
All numbers purchased from Twilio or ported over to us are already verified as caller IDs.