This extension validates phone numbers
It will also format phone number to ITU-T E.164 or any other format that LibPhoneNumber supports(for full support see libphonenumber\PhoneNumberFormat)
// add this in your model
use mikk150\phonevalidator\PhoneNumberValidator;
// use the validator in your model rules
public function rules() {
return [
[['phone'], PhoneNumberValidator::className(), 'country' => 'US']
];
}