howard91447448 Assuming you have a custom extension Acme\Howard located extensions/acme/howard, you will create the notification channel class (ex. CustomChannel.php) in extensions/acme/howard/smschannels/ and the notification template in extensions/acme/howard/views/ sms/custom_channel.blade.php, then register both channel and template as follows:
public function registerSmsNotifications()
{
return [
'channels' => [
'custom' => \Acme\Howard\SmsChannels\CustomChannel::class,
],
'template' => [
'acme.howard::_sms.custom_channel' => 'Custom SMS Template description',
],
];
}