Due to local regulations, some phone numbers require the end user to be located within or outside of a geographic boundary. To purchase these numbers, you will need to provide, and keep updated, a valid business or personal address that satisfies the requirement. The address must be the residence or place of business of the individual or entity using the phone number. If you are using the numbers directly, the address should be yours, and if you are reselling the phone numbers, the address should be that of the end user (i.e. your customer).
There are three types of address requirements:
Any: Requires an address anywhere in the world.
Local: Requires an address that corresponds to the phone number's prefix. Depending on the local regulation, this can be the matching country, region or city.
Foreign: Requires an address outside the phone number's country.
When purchasing phone numbers with address requirements, Twilio will require you to file a qualifying address with us before you are able to purchase the phone number. After creating that address once, it can be used as many times as you’d like for the project on which the address was created. We will use this address in the event that we are contacted by authorities.
If you own several phone numbers for different customers in a particular country, we strongly encourage you to add multiple addresses - one for each customer. This is because regulators in countries with address requirements have the expectation that the address on file corresponds to the business or person who is receiving or originating calls from that number. We also strongly recommend that resellers of Twilio’s products use the parent/subaccounts structure to separate phone numbers and addresses of different end users. See “What is a subaccount?” for further information.
A detailed list of countries that have address requirements can be found here, although the best way to filter is using the list filters on Twilio’s AvailablePhoneNumbers resource or the Advanced search features within the API.