These are the SMS settings for the plugin.

SMS provider
In order to send SMS, you need to add your Twilio API SID, API AUTH TOKEN
To create a Twilio account, click on the following link: https://www.twilio.com/try-twilio
API SID
Get the API SID from your Twilio account.
API AUTH TOKEN
Get the API AUTH TOKEN from your Twilio account.
SMS phone number
This is the phone number to send SMS it should be in the following format (+)(country code)(area code)(phone number) e.g +15024658206
In order to send SMS this phone number must be registered with twilio.
If you are on the twilio trial plan please use the number that they provided you.
SMS to driver
This option lets you send SMS to the delivery driver when a new order is assigned.
SMS to customer
This option lets you send SMS to the customer when the order is out for delivery.